what's the difference between a 85 and 115 up engines

[sony224422]

Is it just the carb size

 

[iwombat]

Re: what's the difference between a 85 and 115 up engines

What years/models are we talking about?

 

[sony224422]

Re: what's the difference between a 85 and 115 up engines

1977 on both years.. they are v4's

 

[Dhadley]

Re: what's the difference between a 85 and 115 up engines

The 85 has a standard bore of 3.375 and the 115 is 3.500. Besides the bore difference there are port area and port timing differences. Obviously the heads and carbs are different.

Yes, you can make a 115 out of your 85 block. Yes, you'll probably be dissapointed at the results vs. the work & $$.

 

[sony224422]

Re: what's the difference between a 85 and 115 up engines

the only reason i ask is because i have 2 part motors that are 115's Both with good carbs and everything is fine on both besides the heads.

 

[Dhadley]

Re: what's the difference between a 85 and 115 up engines

As long as the 115 powerheads are on 20" motors, the bolt patterns are all the same.

 

[sony224422]

Re: what's the difference between a 85 and 115 up engines

all 3 of the motors are 20". would i gain any power by switching anything over from the 115's to the 85? or is it basically going to be the same power?

Also, i was told to pop the heads off the 85 and change the 4 rubber plugs for the water passages that direct the water. is it worth changing this.. also what else should i do to make sure i don't end up with another engine with a broken ring or siezed engine.

 

[Dhadley]

Re: what's the difference between a 85 and 115 up engines

Anytime you change the head gaskets or have the heads off for any reason, yes - change the deflectors. Cheap and easy.

If you've had issues with broken rings it's most likely from lugging. If the motors are set up so they're capable of the right rpm it's unlikely you'll ever break a ring.

 

[sony224422]

Re: what's the difference between a 85 and 115 up engines

Well one one engine i broke a ring.. on the starboard side ( i've heard this side runs a little hotter than port).. it just seemed to happen from old age and use from the engine ( it was a 1977 johnson pushing a 17 ft grady ski boat)

the second one i seemed to have overheated and seized.. not really too sure what happened other than the port lower piston was seized completely and had a rusty cylinder wall by the time i pulled the head after pulled the boat out of the water the day it siezed.. leading me to beleive it sucked in water some how.

Where are those deflectors located?