View Full Version : Swapiing a 120HP to a 125HP powerheadQuestions

12-20-2008, 09:17 PM
"I have a 120hp Force L drive on a Bayliner 1991 boat, I can get a 125hp powerhead of 1989 vintage are they interchangeable???Anyone know??The 125hp 1989 is only a powerhead with out any carbs or electrics or anything just a good powerhead, My 120hp has 3 bad cylinders, But can I swap all the parts over to the 125 block, Thanks guys."

12-21-2008, 09:34 PM
"Bruce, the L drive would have had a Merc ignition system. The 125 would have a prestolite - totally different.

I have often toyed with the idea of seeing if I could make the merc system work on a prestolite, but certainly would not advise that it could be done.

The carbs would most likely fit since they both appear to be tillotson's, although the jets in the 125 model would be different, but not much and as long as they bolt up correctly, not worth rejetting.

If you can get the powerhead cheap it may be worth the experiment, but it is by no means a direct swap over...."