Yamaha 2009 40hp 4 stroke issue

[Doecrusher]

Id imagine they're way more than the 200 to get them clean... Do you happen to know wot rpms before you noticed a drop in speed??? What prop is on there now??? If it were me I'd prop it closer to 6k so you don't lug the motor if you add more weight than your usual load...

 

[Doecrusher]

Did he happen to do a leak down test on the motor?? That'd tell alot more than a compression test with it being a 4 stroke...

 

[Chiflyguy]

Did he happen to do a leak down test on the motor?? That'd tell alot more than a compression test with it being a 4 stroke...

No
I ended up hiring a self proclaimed outboard mechanic.
That didn't work out the best.

 

[BuckWild]

I've had bad gas experiences two times. By bad gas, I mean it had water in it. Both times from a marina.

Both times it was a very intermittent sudden loss of power, then boom back to running normal. then loss of power, etc...

Wouldn't think it would be a steady loss of power issue.

Sounds like a prop issue to me.

 

[Chiflyguy]

I've had bad gas experiences two times. By bad gas, I mean it had water in it. Both times from a marina.

Both times it was a very intermittent sudden loss of power, then boom back to running normal. then loss of power, etc...

Wouldn't think it would be a steady loss of power issue.

Sounds like a prop issue to me.

I've been running the same gas since I started having the issue.
I'm gonna take the wife on a long boat ride and burn some up.
When it's about empty, I'm gonna run to the gas station and get 10 gallons of 100% gas and go from there.
Mechanic checked the prop but I question his knowledge.
Try and help a guy with his new business

 

[nwsg76]

Mick Thompson borrowed my boat once and put good gas in it... would not run worth a darn.
My yamaha 4 stroke 40hp likes the cheap and mid grade stuff.

 

[Pilchard]

if the injectors are clogged your performance will continue to get worse.

It's been years since I paid to get some cleaned but I think it's was $89 each and that was at least 6 years ago.

They are supposed to be cleaned every 500hrs anyways so I would do it unless you know it was done within the last hundred hours or so.

Also, it was my original diagnosis… so I'd say your guys is probably right.

 

[Pilchard]

Also, he should have inspected and replaced the VST filter. If the VST was dirty, the injectors need cleaned.

 

[Pilchard]

One more thing. The mechanic should remove the whole fuel rail with the injectors attached and send away the whole assembly to be cleaned. In FL I had a shop that would clean and flow test then locally. Perhaps there is one near you?

 

[XCR-2]

Could have spit a reed

 

[kaizen leader]

Seem to have lost 5-6 mph lately.
Haven't checked the prop for a ball of fishing line yet, bought a new fuel/water separator filter I have to change, blah blah blah
Tilt and trim are operational.
Did recently fill up at a Marina
Anyone have a tip.
I have done 0 troubleshooting at this point.

Try Lucas fuel treatment. Stuff is great. You might also have bad gas. I have had bad luck with gas from marinas. Good luck.

 

[00bucshot]

Someone may have already suggested this. If your boat has been in the slip for awhile, the bottom could be algae coated and impacting performance.

 

[shrimphead]

Someone may have already suggested this. If your boat has been in the slip for awhile, the bottom could be algae coated and impacting performance.

does not take much algae to slow it down check propeller too

 

[Tenntrapper]

Could have spit a reed

It's a 4 stroke. Unless I'm grossly uneducated on these things, it shouldn't have reeds.

 

[Chiflyguy]

Bad gas was the culprit
Back to 27-28 mph

 

[7mm08]

Glad you got it worked out.

This guy IS A MECHANIC, an engineer, and a Captain. The ONLY GUY that would touch my Yamaha. He diagnosed the problem on my buddy's Yamaha here in Beaufort that two " certified " mechanics couldn't…..

Tell him Phil sent you!

 

[kaizen leader]

What was wrong with it?

 

[kaizen leader]

What was wrong with it?

Never mind. I see. It was bad gas.