ProV 150 loss of power

[Acraft0825]

The engine is a 1990 ProV 150.

A couple days ago while I was running across the lake I had a sudden loss in power. The boat was cruising at around 4000RPM when all of a sudden I felt it shudder and drop to around 3200RPM. I tried to give it a little more throttle but all I could get it up to was 3500RPM, but it would surge like it wanted to run faster, but wasn't getting enough fuel. I pulled the throttle back and idled to the ramp with no isues.

Today is the first day I get to work on it to try and track down the problem. 3 months ago I did a complete rebuild of the cards with all new parts, so I'm hoping its not that. My first thoughts are rebuild/replace fuel pumps. Check high speed jets in the carbs. Compression check. Test spark. I've already replaced every fuel line in the boat, and there is a water separator installed. I also run ethanol free fuel.

If anyone out there can think of anything else to check please let me know.

[99yam40]

Sounds like you are heading in the correct direction.

checking/testing fuel pump system and looking for restrictions to the pumps is the 1st place I would be looking

[Acraft0825]

Well after getting home from work and getting out everything I needed to start diagnosing my power loss problem. Spark tester, compression tester, and the tools to pull the fuel pumps and carb jets. As I took the cowling off I saw one of my plug wires disconnected. Man do I feel like an idiot, sometimes it really is the simplest solution.

[99yam40]

well in my opinion it is better on the pocket book to find a plug wire off.
You need to make sure they are all the way on and fit properly so it does not do it again

[Acraft0825]

Thanks for the advice. I feel like this us a sign.

I've had the engine for 3 years and I put new plugs in it when I got it, so I'm going to go ahead and replace the plugs and wires.

[TownsendsFJR1300]

I just had a very similar situation with my F150 the last two months:

http://www.yamahaoutboardparts.com/f...s-th26221.html

Low hours, (200) original plugs.

Put in new spark plugs, runs 100% again!!! Absolutely NO hesitation, nice and smooth thru the rev range.

All the wires were tight too. I put a little dielectric grease in the wires caps when re-installing..