Force 70 hp powerhead swap

[Lakeside92]

Hi - I have a 94 Force 70hp and I am looking at a 91-94 90hp powerhead. Will it fit? Can I put the 70hp carburetor and manifold on it, and electronics from a 70 hp?

 

[Nordin]

Will not fit.
The 70Hp is a complete different engine.
This 70Hp is a 3 cylinder engine fed by one carb!!!!
Not a really good engineerd engine!!!

 

[jerryjerry05]

The 91-94 is the same motor after 94 they changed to a lot of Mercury parts.
The 70 was introduced in 91 and pretty much all through 94 the parts were a swap.
So your powerhead should change over.
The only thing is the 91A/B had a different adaptor plate from the 91C but the block is the same.
The old 70(Chrysler) had the 3 carbs and pretty much nothing will change over.

 

[Nordin]

Am I missing something jerry?
Isn´t he talking about to swap from a 91 70Hp Force power head to a 91-94 90Hp Force power head.

From what I know it will not fit.

Older Chrysler 70Hp power head will fit on a 91-94 90Hp Force or 87-89 85Hp Force.

 

[Lakeside92]

Hi Nordin, Hi Jerry, - That is exactly what I'm talking about - I have a 1994 Force 70hp and I am considering putting on a 91-94 90 HP powerhead. It appears to be the same cubic inch 3 cylinder block, but I am wondering if the crankshaft will mate to the driveshaft or if there is anything else that could be an issue. This is a short block option and doesn't include any electronics, carbureators, etc. I know the 70 hp is a bit of a "parts motor" but I will say that it has performed extremely well on my pontoon since new. It just needs to be refreshed. Compression on all cylinders is 70. All same but very low.

 

[Nordin]

Lakeside does your 70Hp have only one carb?

I have never worked with these 70Hp only read about it.
Have the factory service manual for the 1991 models and from that I see it has a different LU and it looks like a Mercury style LU.
I am not sure but I do not think it will fit.
Maybe Jerry knows more about it.

 

[jerryjerry05]

Everything should fit.

Mercury parts after 94 on most other models.
Mercury bought Force and introduced the 70 and used their parts(lower unit etc) on the

The 70# is probably the gauge or the way it was taken.
All 3/70 shows the cyl are probably ok just need a better gauge????

 

[Lakeside92]

Thank you - Yes - 70hp has only 1 carb. Dealer did the compression check but I haven't run motor in a while as I'm refurbishing the pontoon. I'll take motor off and double check compression before I get too involved. Even after compression check, motor ran great and started fine. Thanks all.