prov 150

Just new to this, but I have a 1987(?) pro v 150, compression is around 120 for every cylinder. We got this boat with motor last year and used it 7-8 times so far. Had it out last night, it ran GREAT for 1/2 mile. RPMS fell to under 2000. Parked the boat, tried later and no luck. (it starts and runs GREAT if you just use the throttle. 6000 rpm. When you put it in gear is when it does not run good.) When we left the lake, the boat ran to 4700 rpm and that was it. We had it out two nites before that. Pulling a tube back and forth, the temp buzzer went off. Later pulling a skier straight, everything ran pretty good, but didn't get the speed we did last year. 48mph this year V 58 last year. I did put in a new water pump last fall. I checked the thermostats and they opened and closed fine.(today) The thermo sensors appear to show continuity at close to the correct water temps using an ohm meter and varied temps of water. I did drain the gas tank last year and have all new gas this year. Fuel sediment bowl is clean. Any help before I take it in to the dealer, ouch, would be appreciated! Boat has only been in fresh water, and looking into the thermostat holes with thermo removed, it sure looks clean. There is spark to every plug also at idle.
Thank You in advance!
Tim

[Tucker]

It sounds like the only thing you didn't replace is the Pressure Relief Valve. It's on the back at the bottom and has a 1/2" hose plugged into it. Looks like you may have some carbon build up if she won't idle right.

[jb123]

with the varying rpms sounds like you have a fuel restriction, air leak in lines, dirty carbs or dropping a cylinder. that motor should turn 6k all the time.