AQ125 2.1 losing power sometimes -need suggestions

[wrenchtosser]

Hey everyone. Just got an old boat- ran like a top then all of the sudden one day at full throttle it started to slow down. Almost to a crawl. It idles fine, never misses, then after I let it sit for a minute or so it will go right back uo to 3500 rpm and be fine. Then it slows down again. I pished it hard tonight (full throttle even when it was dying) and I thought I heard a few pings. Being a car guy this SOUNDS like an exhaust restriction but honestly it is just a guess. Any common things on these to look for?

Also, if I get this fixed I PROMISE to post the resolution. I found plenty of posts with similar issues with no resolutions posted.
Thank you in advance!

 

[captmello]

Re: AQ125 2.1 losing power sometimes -need suggestions

To me, it sounds like you're not getting enough fuel to the carb. I would change out the fuel filter and make sure the fuel isn't restricted. Also make sure the vent from the tank isn't clogged. If you can do it safely, pull off the fuel line running to the carb, stick it in a fuel resistant container and turn over the engine without starting it. The fuel pump should pump as much as a pint of fuel into the container in 15 sec+/- of cranking.

 

[wrenchtosser]

Re: AQ125 2.1 losing power sometimes -need suggestions

Thank you. I have looked everywhere and do not see a fuel filter on this beast at all. Do you know where it might be?

 

[Alan Lloys]

Re: AQ125 2.1 losing power sometimes -need suggestions

I don't know what boat this engine is in, but I have the B version in my Bayliner which I think is near identical.
There is no fuel filter or water separator on there. The only thing protecting the carb against debris is the small screen in the gas inlet on the carb and supposedly also a screen on the pickup from the fuel tank.

I installed an after market fuel/water separator and filter on mine for peace of mind.

I also have a 125A engine as a spare that I have partially rebuilt. In my experience these engines are very sensitive to timing, ignition and carburetor. So I would check all of these items.
Also check that the timing belt has not slipped a tooth. I have heard about that happening for others which will really mess with things.

In my 125A spare engine I had to replace the points and rebuilt the carb, lap the valves and set the timing belt correctly to get it going.

Hope this helps.