1997 yamaha prov 200 loss of power

[Craig]

It seems my motor will run good while it is still cool but after warming up it gets very sluggish and sounds like it is running on 4 cylinders. I checked the fuel and carbs and that does not appear to be an issue. I am told this is probably the cdi unit or something electrical breaking down? Compression is good..Any suggestions

[jb123]

runs good under LOAD or on muffs in the driveway while its cold? if its been more than 2 yrs or has sat for more than a month or 2, i would suggest a carb cleaning.so many want to blame ignition parts, of the 9 yamahas ive owned, never have i seen those parts go out.

[Craig]

Sounds good under muffs and the initial run down the lake but after that the problem seems to appear. I use this often so it rarely sits for long. I recently added high performance heads and the exhaust tuner from hydro tec and have changed the jet sizes to accomodate. The first run after the jet change was good but still lacking and after the spark plug check, it showed I was running lean on 4 cylinders. I went up 1 size on those cylinders and headed back to the lake only to get in a boat that ran fairly strong the first go around but now sounds like a tug boat with little power. I would bet I could run it today and it would come out strong to start but finish as it is now after a short run

[jb123]

if you want to rule out the electrical, put the original parts back on and see.

[Craig]

Don't think I will be changing heads and removing the new exhaust tuner again, very time consuming and gaskets are not cheap. I have gone back to the carbs to be sure there is not build up somewhere that I have not found before I have the electrical system checked out. Soaking them now.

[jb123]

Ive had to redo mine up to 3 times before....i would try to keep the carbs stock first, then after it seems to run ok after the mods, then start tweaking them. Ive had about 11 yrs of great use from my pro-v, maxed at 69 when i first hung it, so i never tried to tweak it.

[Craig]

What did you re-do? The cleaning did not help and the motor continues to run sluggish during the hole shot and on top. It has a little mid range thump but thats about it. I have lost around 600 to 800 rpms at wot. I have read where this could be the stator ring but who knows? Unless someone can tell me what else to check with the fuel, I guess it's time to look at the electrical side of things??

[Ken]

Craig,
I'm gonna butt in here and give you my 2 cents worth. What you are describing sounds like it could be a faulty fuel pump/pumps. If the pump/s have never been changed - I would at least do a test on them per the Yamaha shop manual.
In a high performance outboard like yours, a lot of owners routinely change out the fuel pumps every 4-5 years.
Good luck,
Ken K

[Craig]

I replaced the old pumps with an electric holley pump with a regulator a couple of years ago. Also, just replaced the old electric with a new quieter version. I unhooked the fuel lines and let the pump run for a few minutes to make sure it wasn't shutting off or possibly a line collapsing but found no issues there either. I am getting plenty of fuel. Any other suggestions would be welcomed

[jb123]

you have done so many mods there may be no coming back, even to what the stock motor would produce, good luck.

[Ken]

Craig,
Wow, you have a real hybid racing engine on your hands - we are in unchartered waters.
Are you sure that new pump is delivering enough fuel after warm-up and at high speed? If so, then I guess ignition would be suspect - and yeah, I would suspect the CDI as the main candidate.
If I were you, I would get some cooling agent that comes in a spray can, like is used on printed circuit boards (Radio Shack?), and run the motor and get it to act up - then quickly cool down the CDI with the cooling spray, and see if that does not temporarily fix the problem.
You obviously have a thermal related problem, question is - is it fuel or ignition?
Let us know what you find out,
Ken K

[Craig]

Thanks for the feedback. I will let you know what I find out..

[Craig]

You convinced me that my problem was more than likely fuel so I stayed with that and you were right. The regulator for the holley fuel pump was bad along with a collapsing fuel line. I was also running a little "fat" so I went down 1 size on the main jets. Thanks for your help