2.5 mercruiser low rpms at WOT what to check??

[keltie]

we have a 88 renkin elite...2.5 merc with 3.0 carb. rebuilt by previous owner. rpms and power is our problem. only get 3500 with 5 adults and 3800 with 2. what should we look for to fix this. changed sparks, compression on fron 150 and centres 120-125. we have a 17 prop. it seems really sluggish at wot and we bought it for skiing. what else should we be checking for. ignition seems to fire ok. we thought about adding restore for the engine compression. is our compression really all that bad considering it's a rebuilt??

 

[Rhadley]

Re: 2.5 mercruiser low rpms at WOT what to check??

Are you getting good fuel flow? Maybe the filters need replaced. If it runs ok at all other speeds and during acceleration, that would be my first guess. <br />Compression does sound off a bit, though. Did you warm up the engine before checking?

 

[keltie]

Re: 2.5 mercruiser low rpms at WOT what to check??

we cleaned the filters and compression was after engine warmed. it is really bogged down at all speeds actually. don't have a speedometer just rpms on guages. <br />my husband says there is also blow by? whatever that means. he's just hoping it doesnt need rebuild...already done by previous owner but no idea how mechanically inclined he was. any other little things that we can check before moving on to big stuff. apparantly could be a gasket too? but need to to take it more apart to check that is that right?<br />takes a while to get on plane too...seems unlikely to ski with this boat unless we get more power!<br />by the way it's 17 feet with a 17 prop. will prop improve rpms AND power and effective plane?