1998 mercury 175hp on a 1989 mercury 150hp midsection

[TyElrod]

hey guys, new to the site so hope im getting this right. so what i have is a 1998 175hp mercury black max that runs great but it has an XL shaft . my old motor that is a 1989 150 hp blew its power-head. but has the jet pump and a long shaft. so my question is can i swap the 175hp power head onto the older 89 midsection? if so what will it take to do this? and if it doesn't work, what year and hp midsections will work? thanks ahead of time guys!

[njj502]

Swap the power heads and go boating again. The adapter plate (between the mid and power head) is what really matters. You should have a direct swap there w/o messing with adapter plates.

[TyElrod]

nice! what should i need for gaskets? id like to have everything prepared and ready to go so i can knock it out in a couple evenings since ill be borrowing a buddys shop. any tips or tricks on this swap i should know?

[njj502]

Power head base gaskets and whatever you will swap over or open up to inspect. Pretty straightforward swap really

[TyElrod]

awsome thanks man! you just saved me alot of money!

[johnboy 88 vegas]

Just a fyi...pretty much any 2.0, 2.4, 2.5 fishing motor will work on that leg. The racing motors have a different cool strategy than the fishing motors but needless to say they will bolt on as well...probably just won't cool properly.

[TyElrod]

ok so now that we got that lined out any idea how many bolts hold the powerhead on the 1998 175hp? any tricks to breaking that thing loose? think its seen a little salt but has very little rust anywhere on the motor or block. just some surface rust on the tiller bracket.

[njj502]

8 studs I believe

[rock]

ten studs

[njj502]

What he said.

[TyElrod]

any ideas of where i can find a diagram? does the lower cowling come off before the power-head or do i have to dig down in there to get to studs? just trying to compile all the info i can before digging into a great running motor don't want to mess this up to bad lol

[njj502]

Go to mercury parts express and plug your serial number in. It will give you a parts breakdown. If you can get a Merc manual they ere not that expensive. I think $75 or so will get you the book that covers 150-225 2.5L engines.

[wired247]

any ideas of where i can find a diagram? does the lower cowling come off before the power-head or do i have to dig down in there to get to studs? just trying to compile all the info i can before digging into a great running motor don't want to mess this up to bad lol

Yes, You have to take the lower cowling off to get the nuts off. No other way. Once you figure out that lower cowling thing its a ten minute job getting it off there.

[rock]

4 more screws (2 in front and 2 in back) and a couple wires and you're ready to roll