Yamaha 40 Help

[bjohnson86150]

Hello. I have a 2013 Yamaha 40 tiller on a 16 foot Xpress. Back in March I was fishing in the river. I left the spot I was fishing and started up River to another location. My motor started cutting back at full throttle. It cleared up and I ran back to the landing with no other issues. I came home and serviced my motor. ( oil change, changed foot oil, new fuel filter and new spark plugs). I then went to the lake several times and everything ran fine until a week or 2 ago. My engine starts and runs fine when I first get to the lake. We stop and swim or fish for awhile and when I take off my engine cuts back and bogs at full throttle. I have ran a can of seafoam through the last tank of gas (ethanol free) and it still won't plane out. I pump the bulb and nothing changes. I've checked all of my fuel lines and nothing appears to be dry rotted or cracked. I have tired a new fuel tank and fuel line from the tank to the motor and it's still cutting back. What could be my problem? Thanks

[hickory]

Trash blocking jet in carb?

[CUducks648]

Is it firing on all cyclinders?

[bjohnson86150]

It has fuel injection. I'm figuring I may have some trash there.

[bjohnson86150]

Yes it's firing on all cylinders

[Gone South]

Check fuel pressure

[Bownut]

Check for a loose ground wire on the motor.

[Rubberhead*]

Sounds like your fuel/water separator, if you have one, needs to be changed.

[kent521]

If you have good fuel pressure send your injectors out and have them cleaned I use Injector renew out of Wilmington , if you mail them out on a mon tue you will get them back on or before Friday

[BigBallin]

This will probably sound dumb but are you sure the prop hasn't been damaged or is starting to spin on the hub? Im not at all familiar with how Yamaha is set up in terms of prop bushings or if it uses an external "rev limiter" or if its part of the ecm or if it even has one. Could possibly be pinging off of it which will feel and sound like a skip or stutter and, if you don't have a good tach, could be quite hard to notice because it may only be a hair more rpms than your normal WOT revs. Kinda a long shot but definitely a possibility if none of the other suggestions pan out. good luck

[bjohnson86150]

Thanks for the guidance. I did change the prop and it's still acting up.

[BigBallin]

where are you/boat? what city or county I suppose I should say.

[Waldo]

Sounds like a fuel issue, I'd start there. Then compression test after it's good as hot if you don't get anywhere with the fuel.

[Rubberhead*]

Duh - check the water pump too. Most/all Yahama's have a thermal "switch" that throttles gas if the engine overheats. On the initial run you might be alright because there is some cooling water flowing but if you cut the engine and sit for a few minutes the heat build-up may be enough to throttle fuel if you try to run WOT. I had this happen on my 200 Yamaha even though it was peeing strong. New water pump fixed it right up.

[bjohnson86150]

Im in Honea Path. The water pump could be the problem. Would the water it's peeing out be hotter than normal if it were the water pump. I've always checked to make sure it was peeing but never have really felt the water.

[willyworm]

If its peeing a good stream that's probably not your issue.

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[Rubberhead*]

If its peeing a good stream that's probably not your issue.

That's not always the case.

[Waterfowler]

Fuel pump. Had the same issue. Battled it for months. It'll get worse. To the point it won't run.

[LPDstumpjumper]

Which fuel line and bulb are you using? I had an issue with the liner in the Atwood one from Walmart collapsing. One of the best things you can do is run automotive fuel line and an OEM Yamaha bulb. Also replace your lines under the hood with some kind of transparent Tygon. Fuel-line.com is a good supplier. Then you can see if you have too much air in your lines and you can isolate the issue.


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[LPDstumpjumper]

Next time it happens, pump your bulb and see if it fixes it.


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