2005 Yamaha 150hp four stroke hot start issue

[Mrob]

Hello folks. Owner of a 21’ 2004 Chaos and she’s been a fishing machine until lately. She starts right up and then after we turn it off after running a bit she won’t start- until 15-20 minutes later. Heard this year model had hot start issues and this is pretty symptomatic of that issue. Any suggested remedy’s for this issue?

All new plugs, Fuel filter, oils change, changed fuel bulb.

I also heard Yamaha doesn’t make the kits anymore…

Thanks in advance for any ideas/help.

 

[Dave LeGear]

IF you prime the engine (squeeze the bulb) again does it fire back up?

Next time that happens also loose up the fuel cap and see if that helps?

 

[Mrob]

It actually doesn’t. Tried that a number of times and replaced bulb and hose to engine.

Will try to loosen fuel cap.

Thank you for your response!

 

[Dave LeGear]

Check the anti siphon valve at the fuel tank fuel pick up, they were pretty cheap that the OEM installed, and could have (should have) gone South a long time ago...

Poor fuel quality / wrong blend in the tank for the present conditions, can also allow the fuel to "boil" in the lines and cause a vapor lock state and basically starve the engine for fuel. Usually, the fuel boils the worse in the lines that run right near the block since that is the point of the greatest heat.

Also (this list can go on for a while) as things heat up they expand and allow for vacuum leaks. Better check all the hoses and bolts near block (intake manifold really pay attend too) and make sure they are snug and at the correct torque specs.

Plug wires and coil packs can also break down under heat.

Hope this helps!
Dave

 

[Dave LeGear]

So, what did you find as the root cause of the engine performance issue?