Motor trouble

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Hi I am looking for info on a 2002 125 mercury elpto. I had my boat out today and it was running fine. then left to go to another spot and the motor would not run at full speed it would run fine when at lower speed but hardly had enough power to plane out. It would run about 15mph under normal top speed? Thanks in advance for any help!
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Check all hoses and fuel lines for kinks, splits, and air leaks.

Any time a motor runs fine at lower speeds, but bogs down at higher speeds, the first suspect has to be a fuel flow or air leak issue that is interfering with the delivery of enough fuel to keep the motor running at higher revs. Carefully inspect every line you can find for signs of leakage or cracking. Pay careful attention to any clamps that may have a split hose underneath.

Grouse

I had a coil go bad on me and acted similar. The engine would start and idle just fine. Under load it acted like it had no power, tried to rev up but acted like it was way over propped. Then all of a sudden, next time it might take off just fine. Turned out one coil was failing and would intermittedly fire or not fire. I too thought it was fuel related at the time. Checked everything fuel related before taking it in to a dealer.

I’d still check fuel system first.

Yep, check fuel lines and filter first. If those all check out, I’d suspect a coil.

Huntindave wrote:

Then all of a sudden, next time it might take off just fine. Turned out one coil was failing and would intermittently fire or not fire. I too thought it was fuel related at the time.

Key point here. Fuel problems are rarely intermittent. If you have a fuel issue or air leakage, it won’t likely just disappear.

If the problem suddenly goes away for a while, then we switch focus to electrical. I would agree, the coil is the next logical step in that direction, but always check for fuel delivery issues first. If it’s a cracked line causing air leakage, it could be 3 minute fix.

Grouse

Ok thanks I’m thinking maybe fuel like your saying. I pumped the bulb and thought I heard a little air. It also hasn’t been getting as hard as normal. Also do you know if there is a vent on top of the oil resevoir I knocked it and a hose fell out of the opening? Thanks for the replies!

So I took it to a mechanic today and he says he thinks it’s a coil after testing. Hopefully won’t run me too much. He ordered the part today so will be without boat for a few days anyway.