i just put new engines on my 96 Fountain 31ft sportfish. used to have merc 225s... went to merc 250s. The boat is now very difficult to control at speed when trimmed up just 25-50%. wondering if this is props or shaft length or what. any suggestions would be great.

Thanks

Dan

Did you change shaft length? What kind of steering? What is the toe set?

Did you switch prop rotation? Are they turning in or out?

look at the transom to see if the new engines were mounted at the same height. cant see a professional changing shaft lenghth , but you never know. also all of the above. and shove engines from side to side to make sure they didnt crack the the steering lines( assuming you have hydraulic) this will tell you if there is air in the lines. oh check the cases for torque tabs and directional zinc's.

good luck

couple things to check, motors spinning in or out? (same as previous) how much of a weight difference with the new? is the motor height the same? are you running the same props? if not are they a different style? the biggest cause is usually allignment of motors or loose steering!!!! toe in about 1/4" is what I have found is most stable after going nuts with a handling problem i was having on my center console, also my prop were way to deep, I had to add jack plates but this should not be the case for you if your at the same height as the previous motors good luck and let us know how you make out

thanks for the info and suggestions guys... i dont know the answers to your questions right now, but i will look into them. going home today so i will tell the marina your suggestions.

Thanks

Dan