1987 Yamaha 115ETLH - Bogging down issue

Hey folks,

Recently picked up this boat second hand and have been running into issues with motor. The motor runs fine and idles great however when I have the boat in the water and apply throttle With engine revving up and beyond 2200RPM (under load) it basically bogs down totally and dies unless I retard the throttle. So far I have checked the fuel system and there are no obstructions and it’s pressure tight. The fuel primer bulb flows correctly etc.

Im a newbie and fiddles with the ignition timing stopper (turned it counter clockwise to loosen it up thinking I controlled the idle speed, realized afterwards where that screw was). So yeah now it bogs down under load. My question is. By setting the ignition timing stopper back to its original position will that allow me to have correct timing advancement and therefore power under load or is it perhaps the doom of clogged carbs starving the motor of fuel?

The idle speed stopper and the upper screw ( maximum ignition advance ) have nothing to do with the bogging.-----Post results of a compression test.-------Clean the carburetors------If motor sat for any length of time with fuel in carburetors , the jets may be clogged.-----Check oil injection system too.

Go to yamahapubs.com and buy the service manual for it. It will tell you how to properly adjust the throttle linkage and timing. But if it was bogging down before you touched any screws, I would say your issue is not related to timing. More than likely, it's related to carbs, the fuel pump or the oil pump.

It looks pretty clean for an '87 though.

The motor is rather clean indeed. Does not negate the fact it bogs down and cannot get it out on the water. The motor sat for “how long” I don’t really know as previous owner didn’t seem to use it much. Perhaps a carb cleaning will do justice in that regard. I will order the kit today for gasket replacements etc. If it is not the timing then it most likely is blocked jets etc. I have a marine mechanic friend who seems to think it’s clogged carbs though he ain’t seen the motor yet

Fiddling w/timing is moot if you haven't 1st addressed fuel system issue. Need to pull carbs then pull all jets. If you don't have a model year specific service manual, nows the time. Soak amd clean jets...you shud be able to see thru jet when holding up to light. Replace the kit and confirm float height to spec. Reinstall. Then you time and sync carbs.

Hey Folks,

So cleaned the carbs. We’re not bad at all. Jets seems all clear!

anyhow I replaced the fuel primer bulb and flushed out the fuel lines. The boat is running great now however the idle was very rich! 4 pilot screws were 3 1/4 - 7/8 turned out. You could literally smell the fuel!!!

My question how is how much to turn out the idle pilot screws? 1987 Yamaha 115ETLH. I found a manual but it is for E115A (1-1 1/2 turns) or 115B (3/8-7/8). Not quite sure which motor I have to be honest.

I have turned the screws out from seated to 1 1/2 turns. Idles fine. Any advice?

Nice.

Most manuals I've read say 2-2.5 turns. But really, that's just a decent starting point. You can fine-tune it by turning them all the way in, then turning them out just enough where the engine will idle roughly.. keep turning out until it gets smooth, note how many turns that took you, then keep turning until it gets rough again, note how many turns that took.. then you just turn it back in halfway between those 2 points.