Cannot get past 2000 rpms

[tshupe5]

I have a 87 Yamaha prov 150 and have had this problem since last summer of hesitation at WOT. Until today it was hit or miss, sometimes would run great and other times it would not. Anyway, I took it out today and it would not get past 2000 RPMs. All of the following were done within the last 4 months: New pumps, new line and bulb, rebuilt all three carbs, checked for blockage from motor to tank, took out fuel pickup from inside tank, and did an external tank test. Nothing has soved this problem. Before today I was at least able to still go out.

 

[cousinabe]

Re: Cannot get past 2000 rpms

If you are certain that the fuel system has been addressed and the engine is not going into oil transfer or over heat reduction, then I would do a timing and link and sync adjustments.

The engine must be timed and synchronized as the final step of a tune-up or whenever the fuel or ignition systems are serviced or adjusted.

Have you performed all steps previously posted by Rodbolt?
http://forums.iboats.com/showthread.php?t=284481

 

[tshupe5]

Re: Cannot get past 2000 rpms

Hey Cousin,

Yes I did test the oil tank sensor and it is functioning properly. Dont think it is overheating because it starts fine and as I start to get on plane it kicks good but almost imediately kicks back down to under 2000 RPMs and leaves me with hardly any power. I took it down to the Yamaha dealer today and one of the techs told me that they are seeing a huge number of boats with fuel issues because of the new mix and he said it could be related and may require some extensive testing. Ihave not had it timed since all the work was done to it so maybe I will get lucky. My hours have been cut to half at work and money is thin. 85 dollars an hour is killing me!

 

[cousinabe]

Re: Cannot get past 2000 rpms

fuel issue could be likely. water in carbs/fuel will do things like this.
you realize water is heavier than gas and will settle in the carb bowls?

 

[tshupe5]

Re: Cannot get past 2000 rpms

Yes,Iam thinking that there may be water in the system.over the past several months I have added stabil, heat, and seafoam.Thought about checking the bowls.How would I go about checking and draining if main tank if test shows water?