crossflow mid section bolt pattern compatibility???

[1976CV16]

good morning! I have a 1978 85 hp evinrude hanging on my boat. The motor runs fine, so I dont want to mess with it, however I picked up a 1977 Johnson 140 hp powerhead. CHEAP! I wanted a spare in case I blew the motor, so I wouldnt be without a boat for long. Will the 1977 140 bolt up to the 1978 midsection? Ive read 1973-1977 are the same except the 140's which are the same as 1978 and newer? and 1978 and up are the same.

 

[Faztbullet]

Re: crossflow mid section bolt pattern compatibility???

The parts online show it uses the same base gasket so it should bolt up but the problem is the lower unit. The 140 and 85 shift different so you need to get a 78 or newer intake to put on the 140 to make it work.

 

[V153]

Re: crossflow mid section bolt pattern compatibility???

Boy I dunno. Might wanna double check on that. I thought '78 was when they changed the powerhead to mid bolt spacing. Meaning pre '78 won't match up?

'78 on the left:

 

[1976CV16]

Re: crossflow mid section bolt pattern compatibility???

I was looking at another forum and found that information. You are right, '78 and up are one way, and 73-77 are another with the exception of the 140hp model which is the same as the '78 and up. Im going to try and find some parts catalogs online and verify. But I agree, if it has the same gasket, it should have the same bolt pattern.

Heres a question for ya... Does the 1977 85 hp have the same base gasket as the 140hp model???

 

[V153]

Re: crossflow mid section bolt pattern compatibility???

Just measure the 140 pwrhead and see which of the measurements I posted it matches.

Purty sure all model crossflows of any given year used the same gasket?

 

[1976CV16]

Re: crossflow mid section bolt pattern compatibility???

this is the information Ive found on an online parts catalog...

1977 140 and 1978 85 use the same exhaust housing adapter (0321545) and gasket (0321727). Mind you, I have never had one of these motors apart, but am I right in saying the powerhead bolts to the exhaust housing adapter?

The 1977 85hp has a different exhaust housing adapter (0317732) and gasket (0318373)

 

[1976CV16]

Re: crossflow mid section bolt pattern compatibility???

LOL v153, why didnt I think of that.

first off, there are 4 sets of bolt holes on the bottom. Starting at the exhaust port, just under the bubble back, I measured and got the same as the 1978. The numbers on the left of your picture. not sure what those extra 2 bolt holes are for. But again, Ive never had one of these apart.

 

[Faztbullet]

Re: crossflow mid section bolt pattern compatibility???

Plus the 77 140 does not have the casting on manifold for shift lever, the 77 uses a clamp style shift lever that bolts to block as the 77 unit shifts backwards from a 78 model...

 

[V153]

Re: crossflow mid section bolt pattern compatibility???

Like FB said ...

 

[1976CV16]

Re: crossflow mid section bolt pattern compatibility???

Would the '78 manifold take care of the shifting issue?

 

[Faztbullet]

Re: crossflow mid section bolt pattern compatibility???

Would the '78 manifold take care of the shifting issue?

Yep...only drawback on the 78 is if it has the orginal pistons as they where pressure backed rings right on edge of piston . Defective t-stats and low quality TCW oil coked up the ring lands and broken rings. Check compression on this "cheap" powerhead...

 

[emdsapmgr]

Re: crossflow mid section bolt pattern compatibility???

You can interchange powerheads that have the dual thermotstat housings. 77 and up. Powerheads with the single stat, such as 76 won't swap. Follow Fastbullets' directions regarding the shift mechanism on the front of the intake manifold. That's the big diff.

 

[1976CV16]

Re: crossflow mid section bolt pattern compatibility???

Great information. Thanks all! The 140 will get torn down and I plan on putting new pistons, rings and fresh gaskets and bearings. That way when I'm ready for it, ill have a brand new motor.

Still cheaper than a "new" outboard, and its nice to know what I've got instead of buying somebody else's problems.

 

[V153]

Re: crossflow mid section bolt pattern compatibility???

Nice to know it's '77 & up. Rather than '78. That increases the parts scrounging arena. I passed on at least a couple cheap '77s cuz I thought the mid bolt spacing was difrent. Thanks emd.