(2000 model) F115TLRY Yamaha 4 Stroke Outboard

[Andrew3754]

Need a little help

I have an 18 foot boat and when I'm out *****ing, I want to run it as slow as possible, so just clicking it in forward gear is the speed I need. My motor will run for about 4 to 6 minutes and then start to shake a little and eventually die. I'm pretty sure its loading up. It will start right back up with no problem and I can see a little smoke, but not much. It wont run in gear below 10 (hundred) RPM for more than 6 minutes, then slowly the RPM's drop more and more and then it dies.
About one year ago I had the entire fuel system cleaned, new injectors and vst box was removed and cleaned, new fuel/water separator, new fuel pump but only one.
This is the first time I used it to ***** at idle speed so I never noticed it had a problem. Other that that it runs perfect.
Does anyone know what the problem could be?

[Sequoiha]

When you are doing this, where is the engine trimmed to, I had a F115 that would load up if it was trimmed all the way down, try trimming it up to just over vertical.

[Andrew3754]

I have to say the motor is probably trimmed close to all the way down, but should that really matter. Wouldn't there be something causing this, I dont think a brand new motor would do this.

I will try it next time Im out, but I really need to get it resolved.

[boscoe99]

You don't have a brand new motor. You have a 15 year old motor. An older motor sometimes simply won't run like a new motor will.

If trimming the motor up will solve your problem, are you willing to spend thousands of dollars to have the motor rebuilt so that you don't have to trim it up to get the same results?

Sometimes it is a number of parts working in harmony that are not working as new that causes the problem. Sometimes it is not just one item that can be replaced/repaired that will solve a problem.

Maybe your rings are worn. Maybe your camshafts are worn. Maybe your valves are worn. Maybe your valve shims are worn. Maybe your bearings are worn. Maybe your idle speed control valve is worn. Maybe your throttle bodies are worn. Maybe the fuel pressure regulator is worn. Certainly you can have the motor remanufactured such that it will operate just as a brand new motor would operate. Only you can tell if it is worth it to do this so as to solve your problem.

What I am suggesting is that sometimes with the passage of time and wear we cannot expect stuff to work as it did when it was new. Wish that my tired old body worked as it did when it was new.

[rodbolt17]

old folks suuuuck
wish I could see though .

trim angle on an EFI motor wont affect running unless the VST needle leaks or the float is incorrectly adjusted.

time to look at why the VST is running out of fuel or dumping fuel.