Loss of RPM in water only 1988 4.3l

[cneste]

Hello<br /><br />I have a rebuilt 1988 4.3 tuned up with new fuel pump and fairly new carb / recent tune up . I can rev the nicely with ear muffs on a trailer but once on the water, The boat will not exceed 2300 at WOT. It might go to 3000 over a straight run in 2 minutes but something is wrong. The Prop has some minor damage to the outer blades but did not affect it the year before. The outdrive is a pre alpha but is very clean inside. Any ideas on this issue??

 

[Watercanuck]

Re: Loss of RPM in water only 1988 4.3l

I had this problem because the boat was stored over winter with only half a tank of gas and condensation built up in the gas tank which quickly turned to water in the fuel. Hoisted the boat up on an angle and sucked all the water from the bottom of the tank, changed fuel filter and cleaned carbs. Problem solved.

 

[cneste]

Re: Loss of RPM in water only 1988 4.3l

Thanks for the reply. I did add marvel mystery oil and stabil. I only had about 1/4 tank of gas in Atlanta, GA. The motor was in the garage due to a cracked flywheel which prevented me from winterizing the boat completely. My 1 year old holley red pump died probably due to bad gas /corrosion and was replaced with a brand new one. I just added 10 gallans of gas today when I took it out. I did check the fuel filter and fuel pressure and that was good. I will clean out the fuel system and replace the water seperator. <br />Thanks for the quick reply.<br /><br />Chuck

 

[cneste]

Re: Loss of RPM in water only 1988 4.3l

I would also like to add that the boat Idles smoothly in the water and does not bogg down. The motor starts smooth and I dont have any hesitations. It runs like it has a governor on it. I can jump on it and it takes off ok, It just wont plane due to lack of power. I put a vacuum gagae on it and it reads about 17 inches of pressure at idle with no fluctuations at all. The engine is a 4,3L bored over .30 with 40 hrs on it. I did seperate the lower unit to replace the water pump assy without any problems. The boat shifts into gear normally and doesn't seem to have aby slippage( removed the prop and checked). Any thoughts are appreciated.<br /><br />Thanks<br />Chuck