Yamaha F200XCA — VST Fuel System: Diagnostics & Parts Research

Boat Info

Boat	2017 Cobia 28 DC (Dual Console)
Engine	Yamaha F200XCA — Inline-4, 2.8L, Digital/Drive-by-wire
Hours	~250 hours
Survey	Michael J. Davidson, SAMS-AMS #1228 — March 28, 2025
Parts Fiche (OEM Diagram)	2017 F200XCA — Fuel Injection Pump 1 (Van’s Sport Center — confirmed working) — Full OEM parts diagram with all 35 VST components, reference numbers, and pricing.
Configuration	Dual engines — Port and Starboard F200XCA

The Symptom

Starboard engine only takes ~2 extra seconds to fire on the first start of the day. Once started, runs perfectly and idles fine. Every subsequent restart during the same outing is instant — no hesitation. Port engine starts instantly every time.

Note: Issue first noticed at the end of the season, so there has been no opportunity to test behavior under hard running load. Subsequent restart behavior and idle quality are confirmed; high-load performance is not yet tested.

Fuel System Overview (Upstream → Downstream)

Tank > Anti-siphon valve > Fuel line > Primer bulb > 10-micron filter
> LP lift pump > Relief check valve > VST > HP pump > Fuel rail > Injectors

Diagnostic Tests — Do These First (Free)

Test 1: Morning Primer Bulb Test

Before starting, squeeze the starboard primer bulb and note firmness. Compare to port bulb as baseline.

Result	Meaning
Already firm	Fuel staying in line → problem on HP side (pump / regulator / gasket seep / injector)
Soft, firms in 2–3 squeezes	Partial bleed-back → LP check/relief valve suspect
Very soft, 5+ squeezes	Fuel draining back to tank → anti-siphon valve or primer bulb check valves
Only starboard soft	Engine-specific problem confirmed — not tank or upstream

Test 2: Double-Prime Test

Turn key to ON (don’t crank) 3–4 sec → key OFF → repeat once → crank.

Result	Meaning
Fires instantly	Overnight HP rail pressure bleed-down → look at VST gasket seep, pressure regulator, HP pump check valve, or leaking injector
Still takes 2 seconds	Rail pressure fine overnight; VST running low on fuel → LP check valve or lift pump

Key Diagnostic Insight

Since only the starboard engine is affected and both share the same fuel tank, the following are eliminated:

Anti-siphon valve
Fuel tank pickup
Main fuel supply line
Primer bulb (likely)

The problem is 100% engine-specific to the starboard engine.

Suspect List — Starboard Engine Only

⚠ Physical Evidence Found: White powder observed specifically and only under the VST — not on surrounding aluminum surfaces. This is inconsistent with general salt air oxidation (which would affect all nearby aluminum equally). It is consistent with ethanol-blended fuel evaporating slowly past a VST sealing surface and leaving mineral/crystalline residue. This elevates VST sealing surfaces to the top of the suspect list.

Physical Evidence Suspect — Investigate First

Suspect 0 — VST Sealing Surface Weep TOP SUSPECT — PHYSICAL EVIDENCE

The VST has two confirmed sealing surfaces that could produce the observed white powder.

The Two VST Sealing Surfaces

Sealing Surface	Pressure	Part Number	SIM Yamaha	Consequence if Weeping
Float Chamber Lid Gasket Main lid seal — seals the top of the VST housing to the body	HIGH (~43 psi)	`6CB-14984-00-00`	$72.65	Bleeds HP rail pressure overnight. Fuel seeps out, evaporates, leaves white/waxy residue along the lid seam. Will smell of fuel. Most likely cause of both white powder and 2-second hard start. Always replace on every VST opening.
VST Water Jacket Seal & Gasket Seals the cooling water passage cast into the back of the VST body	LOW–MEDIUM (cooling water pressure)	Seal: `6CB-14239-00-00` Gasket: `6CB-24482-00-00`	Seal: $30.25 Gasket: $51.30	The water jacket has both a seal and a gasket — replace both every time VST is removed. External weep = cooling water evaporates, leaves white mineral/crystalline scale with no fuel smell. Internal failure = cooling water enters fuel (water-in-fuel alarm). Does not directly cause hard start but needs fixing. Confirm gasket part # with Andy at SIM before ordering.

One-Second Test: Which Seal Is Weeping?

Smell the white powder. Fuel residue smells distinctly of fuel even when completely dry. Mineral scale from cooling water has zero smell.
Fuel smell + residue along lid seam perimeter → Float chamber lid gasket (6CB-14984-00-00 — $72.65) — directly causes hard start
No smell + residue below/behind VST body → Water jacket seal (6CB-14239-00-00 — $30.25) — cooling water weep, does not directly cause hard start

Free Confirmation Test — Do Before Opening VST

Wipe the entire area clean with a rag
Let the boat sit 24–48 hours without starting
Open cowling and smell near the VST — fuel smell = lid gasket weeping
No smell + white scale re-forming = water jacket seal weeping

Repair implication: VST removal is required regardless — the service is overdue at 8 years / 250 hrs. The gasket fix and the overdue VST service are the same job, one trip. Replace every time the VST is opened: lid gasket $72.65 + water jacket seal $30.25 + water jacket gasket $51.30 + top O-ring $30.25 + VST filter $60.00 + HP fuel filter $51.95 = ~$296 in confirmed required parts before any conditional items.

If double-prime FIXES the start (HP side bleed-down)

Suspect 1 — Pressure Regulator HIGH INSIDE VST

Diaphragm bleeds rail pressure back into VST overnight. At 8 years + ethanol fuel, rubber diaphragm is age-suspect even at 250 hrs. Experienced Yamaha techs note regulators more commonly “rust away” than fail functionally — but worth inspecting when the VST is already open. No aftermarket replacement available.

Part	Part Number	SIM Yamaha
Pressure Regulator	`6CB-13906-01-00`	$300.40

Suspect 2 — HP Pump Check Valve MEDIUM INSIDE VST

Built into the HP pump — not separately replaceable. Prevents rail pressure bleeding back through the pump overnight. If failed, replace the entire HP pump assembly. Less likely at 250 hours.

Part	Part Number	SIM Yamaha	Notes
HP Pump Assembly (includes check valve)	`6P2-13907-22-00` ⚠ Confirm current revision and prefix with Andy at SIM — F200XCA diagram (Ref 23) shows `6P2` prefix, not `6CB`. Previous SIM listing was `6CB-13907-12-00` — verify which is correct for ordering.	$421.85–$471.60 (confirm with SIM)	Diagram-confirmed part # for your engine. Confirm current revision with Andy before ordering.

Suspect 3 — Leaking Injector LESS LIKELY EXTERNALLY ACCESSIBLE

One injector needle seat weeping overnight slowly drains rail pressure. Would typically also cause a slight rich stumble or smoke on first fire (not reported — making this less likely). Requires injector removal and testing.

Part	Part Number	Est. Cost
Injector cleaning service (per injector)	—	~$18–25/each (BrucatoFIS or similar)
OEM Injector replacement (per injector)	`6CB-13761-00-00`	Confirm with SIM

If double-prime does NOT fix the start (VST not filling overnight)

Suspect 4 — LP Relief Valve Assembly (aka “Check Valve”) MOST LIKELY — this scenario INSIDE VST — TOP ACCESS

What this valve does: Sits inline between the LP lift pump outlet and the VST inlet. When the VST is full and the float needle valve closes, this valve opens to let the LP pump recirculate rather than dead-head. When the engine is off, the valve should seat and hold fuel inside the VST. If the ball is corroded or stuck open, fuel drains back overnight and the engine cranks 2+ seconds to refill the VST on startup.

Location confirmed by 4Ribs Fishing video at 6:53 (your exact engine — 2.8L inline-4): The valve is inside the VST, accessible from the top. It may be possible to test or replace it by accessing the top of the VST while still in place on the engine — without full VST removal. However if you are already doing a full VST service (gasket, filters, water jacket clean), just do it all in one trip.

DIY test — see video at 6:53:

Access the valve from the top of the VST
Disconnect and blow through it in both directions with your mouth
Flows one direction only → Good
Flows freely in both directions → Bad — replace it
Even a good valve may not be fully airtight at very low pressure — the test is whether it flows freely both ways

Dual-engine advantage: Swap the valve port-to-starboard as a free diagnostic test. If the hard-start moves to the port engine, the valve was the cause — no parts ordered, no money spent.

Part	Part Number	Price	Notes
Relief Valve Assy (original)	`6CB-24460-00-00`	$137.99 (Wholesale Marine — not listed at SIM)	Inside VST, accessible from top. Confirmed 2.8L inline-4 by video at 6:53.
Relief Valve Assy (updated revision — preferred)	`6CB-24460-10-00`	$139.49 (Wholesale Marine — confirm with SIM)	“-10-” = Yamaha revised part. Order this if available. Confirm with Andy at SIM (920-264-0873).

Suspect 5 — LP Lift Pump MEDIUM EXTERNALLY ACCESSIBLE

Worn or cracked diaphragm allows fuel to bleed back toward tank when pump is off. Soft primer bulb in the morning is the telltale sign. Lift pump cycles 10 sec ON / 20 sec OFF below 1200 RPM. No VST removal needed.

Part	Part Number	Price	Notes
LP Lift Pump	`6CB-24410-01-00` SIM carries `6CB-24410-00-00` — confirm -01-00 vs -00-00 with Andy	Confirm with SIM	Externally accessible — no VST removal needed.

VST Contents — What’s Inside

All of the following are inside the VST housing and require VST removal to access:

Component	Part Number	SIM Yamaha	Notes
VST top O-ring (Fuel Filter O-Ring)	`6CB-13016-00-00`	$30.25	Always replace when VST is opened.
Float chamber lid gasket (HIGH pressure)	`6CB-14984-00-00`	$72.65	Always replace — swells with ethanol. [VIDEO 9:04]
VST filter/strainer (“tea bag”)	`6CB-13915-00-00` ✅ Same part as `63P-13915-00-00` (shown in diagram Ref 24) — confirmed cross-reference. Order either; SIM lists as `6CB-13915-00-00`.	$60.00	Always replace. [VIDEO 8:24]
VST water jacket seal & gasket (replace both when cleaning)	Seal: `6CB-14239-00-00` Gasket: `6CB-24482-00-00` ⚠ Confirm gasket # is specifically the water jacket passage gasket with Andy at SIM	Seal: $30.25 Gasket: $51.30	Water jacket has both a seal and a gasket — replace both every time VST is removed. Seal confirmed 2017 F200XCA Fuel Injection Pump 1 diagram. Gasket appears alongside seal on Crowley fiche. Verify with service manual or Andy at SIM (920-264-0873) before ordering.
HP pump (electric, submerged in fuel)	`6P2-13907-22-00` ⚠ Confirm current revision with Andy at SIM — diagram shows `6P2` prefix (not `6CB`). May be superseded to a later revision. Van’s price: $471.60.	$421.85–$471.60 (confirm with SIM)	Inspect when out. Replace only if confirmed bad. [VIDEO 8:35]
Pressure regulator	`6CB-13906-01-00`	$300.40	Maintains ~43 psi rail pressure. Inspect when open; replace only if bad. No aftermarket.
Relief Valve Assy	`6CB-24460-10-00` (preferred revision)	$139.49 (Wholesale Marine)	Inside VST, accessible from top. [VIDEO 6:53]

VST Service Parts — F200XCA

▶ [VIDEO] = confirmed in 4Ribs Fishing VST service video. “In Diagram” checked against 2017 F200XCA Fuel Injection Pump 1 and Pump 2. Prices confirmed SIM Yamaha April 2026.

Component	Part Number	Price	In Diagram?	When & Notes
VST Top O-Ring (Fuel Filter O-Ring)	`6CB-13016-00-00`	$30.25	✅ Pump 1 Ref 5	Always replace. Seals top of VST housing.
Float Chamber Gasket (lid — HIGH pressure)	`6CB-14984-00-00`	$72.65	✅ Pump 1 Ref 30	Always replace. Swells with ethanol — primary high-pressure fuel seal at 43 psi. [VIDEO 9:04] confirmed swelling and difficulty reseating.
VST Filter (“tea bag” strainer)	`6CB-13915-00-00` ✅ Cross-ref: `63P-13915-00-00` — same part	$60.00	✅ Pump 1 Ref 24	Always replace. [VIDEO 8:24] shows significant gunk buildup. Overdue at 8 yrs.
HP Fuel Filter (high pressure output side)	`6CB-24501-01-00`	$51.95	✅ Pump 1 Ref 3	Always replace. Filters fuel on the high-pressure output side of the VST — between the HP pump and the fuel rail. Distinct from the VST tea bag strainer (Ref 24) which is on the LP inlet side. Located near the top of the VST assembly. Confirmed for F200XCA 115–350HP family.
Water Jacket Seal (replace with gasket together)	`6CB-14239-00-00`	$30.25	✅ Pump 1 Ref 16	Always replace both seal and gasket. External weep = white mineral scale under VST (no fuel smell). Top candidate for white powder. See gasket row below.
Water Jacket Gasket 1 (replace with seal together)	`6CB-24482-00-00`	$51.30	✅ Pump 1 Ref 19	Always replace both seal and gasket. Confirmed water jacket passage gasket by position in diagram alongside Ref 16 seal. Confirm with Andy at SIM (920-264-0873) if any doubt.
Intake Manifold Gasket 1	`6DA-13645-00-00` SIM carries `6CB-13645-00-00` at $59.35 — confirm 6DA vs 6CB with Andy	~$59	❌ Intake diagram	Always replace. Manifold must come off to access VST. OEM: never reuse. Tab must seat into slot. See torque notes below.
Intake Manifold Gasket 2	`6DA-13646-00-00` SIM carries `6CB-13646-00-00` — confirm with Andy	Confirm with SIM	❌ Intake diagram	Always replace. Two gaskets required for full manifold assembly. Same fitment notes as above.
HP Pump (pull, inspect & clean)	`6P2-13907-22-00` ⚠ Confirm current revision with Andy at SIM — diagram shows `6P2` prefix. May be superseded.	$471.60 (Van’s) Only if replacing	✅ Pump 1 Ref 23	Pull every time — inspect while out. [VIDEO 8:35] — must remove to access VST filter. Replace only if confirmed bad. At 250 hrs likely fine.
Pressure Regulator Screen (clean only)	`6CB-13906-01-00` Only if replacing regulator	Free to clean $300.40 if replacing	✅ Pump 1 Ref 8	Clean screen under “top hat” cover every service. [VIDEO 10:30] — do not auto-replace regulator. No aftermarket available.
Water Jacket Passage Clean (tool, not a part)	Brass Dremel bits Linked in 4Ribs video description	~$10–15	N/A	Do every VST service in saltwater use. [VIDEO 7:34 — crucial step] — at 8 years flushing alone is not enough. Brass bits physically scrub scale from the water jacket passage.

Intake Manifold Reinstallation — Torque & Sequence

⚠ Torque Spec — Verify Before Reassembly: The OEM Crowley Marine service manual for the 2017 F200XCA specifies intake manifold bolt torque as 10 Nm (7.4 ft·lb). This differs from the 17 ft·lb figure mentioned. Verify the correct spec in service manual LIT-18616-03-49 before tightening. Using the wrong torque risks warping the manifold or stripping threads on an aluminum block.

Torque Spec (per OEM service manual): 10 Nm | 1.0 kgf·m | 7.4 ft·lb

Torque sequence: Tighten manifold bolts in numbered order [1], [2], [3]... [VIDEO 11:49] for torque sequence reference.

Gasket fitment: Fit the protrusion on each gasket firmly into its corresponding slot in the intake manifold. When protrusions contact the fuel rail cover, verify gaskets remain properly seated before torquing.

OEM notice: Do not reuse gaskets — always replace with new. Blowby hose reinstalls with paint mark facing outward.

Conditional Parts

Component	Part Number	Price	Notes
Pressure Regulator	`6CB-13906-01-00`	$300.40 (SIM)	Inside VST. Only replace if confirmed bad. No aftermarket. Often backordered.
Relief Valve Assy — original	`6CB-24460-00-00`	$137.99 (Wholesale Marine — not listed at SIM)	Inside VST, accessible from top. Confirmed by video at 6:53. Replace if double-prime test does NOT fix start.
Relief Valve Assy — updated revision (preferred)	`6CB-24460-10-00`	$139.49 (Wholesale Marine — confirm with SIM)	“-10-” suffix = Yamaha revised part. Order this if available. Confirm stock with Andy at SIM (920-264-0873).
LP Lift Pump	`6CB-24410-01-00` SIM carries `6CB-24410-00-00` — confirm -01-00 vs -00-00 with Andy at SIM	Confirm with SIM	Only if primer bulb is very soft in the morning AND double-prime does not fix start. Externally accessible.

Aftermarket Kit Option

Component	Part Number	Est. Price	Notes
Sierra VST Kit	Sierra 18-79950	~$50–70	Includes VST filter + 10-micron filter + float chamber gasket. Confirm F200XCA fitment first. West Marine. Does NOT include top O-ring or water jacket seal — order those separately.

SIM Yamaha Contact

Website	www.simyamaha.com
Phone	888-231-2392
Andy Munao (owner/tech expert)	920-264-0873 \| andy@simyamaha.com
Free shipping	On orders $149+
Ask Andy about	1. HP pump — diagram shows `6P2-13907-22-00` at Ref 23. Is this the correct # to order, or has it been superseded? SIM previously listed `6CB-13907-12-00` — which is right? 2. Is `6CB-24482-00-00` (Gasket 1, Ref 19) specifically the water jacket passage gasket on the F200XCA? 3. Current stock on `6CB-24460-10-00` revised relief valve 4. Confirm correct manifold gasket # — `6DA-13645-00-00` vs `6CB-13645-00-00` for 2017 F200XCA 5. Service manual LIT-18616-03-49 ($99)

VST Location & Access

F200XCA VST location	STARBOARD side of engine
F250 VST location	PORT side — opposite. Don’t use F250 videos as reference.
Access	Behind the intake manifold — must be removed/swung aside
Tools needed	10mm socket, 12mm socket, universal joint, 6” extension
Before opening	Drain VST via drain screw. Take photos for fuel line routing reference.
Gasket tip	Lid gasket often swells when separated — have spare ready. If it swells, put in freezer to shrink back before reinstalling.

Best Resources for VST Service

⭐ VIDEO (F200XCA 2.8L Inline-4 — YOUR EXACT ENGINE): 4Ribs Fishing — VST Service on the Yamaha 2.8L 4-cyl, 150/175/200HP (July 2024). Same 2.8L inline-4, saltwater, Raritan Bay NJ. Watch this first. Brass Dremel bits for water passage cleaning confirmed as crucial step.
Video (F200/F225 inline-4, older): youtube.com/watch?v=g9Qp6w2akjA (no audio — limited usefulness)
Video (F150 inline-4, same family): youtube.com/watch?v=QT0z9COGYbI
Written walkthrough w/ photos (F150): The Hull Truth — F150 VST Filter Replacement
OEM Service Manual: LIT-18616-03-49 (F200XCA 2013–2018, 2.8L Digital) — $99 at SIM Yamaha. Required before VST work — contains all torque specs, O-ring locations, and water passage cleaning procedure.

Parts Diagrams (OEM Fiche — Confirmed Working)

✅ Both F200XCA diagrams confirmed loaded and verified against our parts list.

⭐ Fuel Injection Pump 1 — 2017 F200XCA/LCA (Van’s Sport Center)
All 35 parts with reference numbers, part numbers, and prices. Key VST parts confirmed in this diagram:
Ref 3 • HP Fuel Filter — 6CB-24501-01-00 — $56.80 (Van’s) / $51.95 (SIM)
Ref 5 • O-Ring (VST top cover) — 6CB-13016-00-00 — $30.70
Ref 8 • Pressure Regulator — 6CB-13906-01-00 — $329.35
Ref 16 • Seal (water jacket) — 6CB-14239-00-00 — $30.70
Ref 19 • Gasket 1 (water jacket) — 6CB-24482-00-00 — $52.05 ✅ confirmed water jacket location
Ref 23 • HP Fuel Pump — 6P2-13907-22-00 — $471.60 ⚠ 6P2 prefix, not 6CB — confirm current revision with SIM
Ref 24 • VST Filter (tea bag) — 63P-13915-00-00 — $58.45 ✅ same part as 6CB-13915-00-00 — confirmed cross-reference
Ref 30 • Float Chamber Gasket — 6CB-14984-00-00 — $73.75

Fuel Injection Pump 2 — 2017 F200XCA/LCA (Van’s Sport Center)
Fuel pipes, clamps, and hose assemblies only (17 parts). No serviceable VST parts — reference only if replacing fuel lines.

Fuel Pressure Specs (F200XCA)

Condition	Spec
Key ON, engine off (within 5 sec)	43.5 psi
Engine at idle	~37–38 psi
After pump shuts off	Some bleed-down is normal; fast drop to <30 psi = problem

Fuel Pressure Test Adapter

Yamaha special tool YB-06946 (OEM # 90890-06946-00). ~$250–300, often backordered. No aftermarket drop-in substitute.

Alternative: Outboard Specialty Tools OST-FST-001 — worth investigating before buying OEM tool.

F200XCA does NOT have a Schrader valve on the fuel rail. The Schrader valve on top of the VST is only for draining/venting — it does not show HP rail pressure.

Check Valves in the System

#	Valve	Part Number	Price	Location	Function
1	Relief Valve Assy (aka Check Valve)	`6CB-24460-00-00` `6CB-24460-10-00` (preferred)	$137.99 $139.49 (Wholesale Marine)	Inside VST, accessible from the top. Confirmed by 4Ribs Fishing video at 6:53.	Prevents fuel draining back from VST overnight. DIY test: disconnect and blow both directions — flows both ways = bad.
2	VST vent/orifice check valve	N/A — inspect only	—	On top of VST, connects to air intake box	Vents VST vapor pressure. If stuck open can cause rich start issues (not your symptom).

White Powder Under VST — Revised Assessment

Originally assessed as normal aluminum oxidation — this assessment has been revised.

White powder found specifically and only under the VST is not consistent with general salt air oxidation, which would affect all surrounding aluminum equally.

Most likely cause: VST water jacket seal weeping (6CB-14239-00-00). The VST body has a cooling water passage cast into its back that engine cooling water flows through. The seal separating this water jacket from the outside is 6CB-14239-00-00. A slow external weep from this seal allows cooling water to drip, evaporate, and leave white mineral/crystalline scale — exactly what calcium-rich cooling water leaves behind on aluminum. This is distinct from fuel residue (which is more waxy/chalky and smells of fuel).

Second possibility: VST float chamber lid gasket weeping (6CB-14984-00-00). If fuel is seeping past the high-pressure lid gasket, it evaporates and leaves a white residue too, but it will smell of fuel and be more concentrated along the lid seam perimeter. This would also directly cause the hard-start symptom by bleeding HP rail pressure overnight.

Quick test: Get your nose right on the deposits. Fuel residue smells distinctly of fuel even when completely dry. Mineral scale from cooling water has no smell at all. That single test tells you which seal is the source.

Either way: Both parts are replaced as part of a VST service. Water jacket seal (6CB-14239-00-00) = $30.25. Water jacket gasket (6CB-24482-00-00) = $51.30. Float chamber lid gasket (6CB-14984-00-00) = $72.65. Replace all three when the VST is out.

VST Maintenance Schedule Note

Yamaha’s owner’s manual does NOT list VST service. The service manual and authorized dealers (including SIM Yamaha) recommend VST filter replacement every 300–500 hours or 5 years. Many techs recommend annually in saltwater/ethanol use. At 250 hrs / 8 years old with no known VST history: service is overdue.

Key Forum Sources

Yamaha Outboard Parts Forum (yamahaoutboardparts.com) — best community for F200 inline-4 issues
The Hull Truth (thehulltruth.com) — good VST service writeups
rodbolt17 — most trusted Yamaha tech voice on the forums: “I have never seen a 4-stroke Yamaha regulator fail… I have replaced a few due to rusting away.”
SIM Yamaha Blog (blog.simyamaha.com) — Andy Munao’s technical writeups, excellent for this engine