AuroraBill

Last summer I somehow blew a hole in my exhaust manifold. I'm a relative newbie to PWCs yet somehow managed to diagnose the problem and replaced the manifold myself. However, when I put the ski back on the water for its test drive it only got up to 40 mph as opposed to its previous top speed of 60 mph (as read on my dash gauge - I realize these are probably not true speeds but that's irrelevant to my problem). Can anyone tell me what may be causing this problem? I found it interesting that I'm reaching 2/3 of its former speed and its a 3-cylinder motor, and thought that perhaps something is wrong with one of the cylinders, but it seems to run "normal" in every other respect. Maybe its something completely unrelated to the exhaust manifold repair.. Help!

ggauvin

Maybe you didn't get the gasket in right. That might block cooling water flow into the block, then it overheats, then your automatic "limp home" mode kicks in. Does the pisser flow freely?
Another possibility is an exhaust leak into the engine bay. Then the motor chokes on its own fumes and loses power. Try a test run with the seat off. Or lash it to the trailer and try a full power test while looking in the engine bay.

AuroraBill

I don't think it's overheating - I still ran it for a couple hours on the lake even though it was running slower (40 mph isn't exactly crawling) and the overheat lamp never came on... Water was pissing out normally. If I take the seat off and run it what do I look for?

ggauvin

You are looking / listening / smelling / feeling for an exhaust leak that is putting fumes into the engine bay.
And, yes, it could be something unrelated to the exhaust fix. You could re-check all the basics.... compression check.... spark check.... fuel check.... examine plugs (does one look different after running for a while??)

AuroraBill

Hmmm.. Unfortunately I live in Illinois and won't be able to get it on the water until Spring. I did check the compression, spark, and plugs, not sure how to check fuel. I've only had these things about 3 years and am learning as I go. I'm really wondering if it might not be something wrong with the motor - maybe the impeller or something like that?

ggauvin

One way to check fuel is to have it under load (lashed to the trailer in the water) with the airbox off. Then spray or drip fuel (wd-40 can substitute... or a propane torch- gas only... no flame...for a short spurt into each carb throat. If that hole had fuel already, the engine will bog down with extra fuel (too rich). But if that hole was too dry the engine will acelerate with more power. It is dangerous to run too long on a lean cylinder (overheat the piston/rings). A good carb cleaning, or rebuild is the fix for a lean hole.

octobon

Change fuel filter, and do as suggested and run it on the flush and see whats up. If you have a major exaust leak it will be obvious. Also, check ignition wires to see if spark hits all cylinders. I use caig deoxit or chemsearch nc-123 on all electrical points.