Powerhead compatibility

[Aquaduck]

Will the powerhead off an 81 115 Johnson bolt onto an 85 90 hp ?

 

[Faztbullet]

Re: Powerhead compadibity

Re: Powerhead compadibity

Yes....

 

[Aquaduck]

No differences ?

 

[Chinewalker]

Re: Powerhead compadibity

Re: Powerhead compadibity

Nothing that would prevent them from swapping over. As for differences between the powerheads, yes, there are some. Differences in the electronics, differences in the carbs, etc. If possible, use the 115's carbs as the 90's may run lean due to the 115 block's bigger porting. Electronics shouldn't be an issue - use what works ? some bosses and mounting points may be slightly different.

 

[emdsapmgr]

Re: Powerhead compadibity

Re: Powerhead compadibity

Some things to watch out for: The newer block is setup differently for the VRO pump. The VRO fuel pump pulse hose is different than the older mechanical port in the side of the 81 block. Probably will want to use the existing older style (premix) fuel pump and the 115 carbs. The 81 ignition harness is setup for a three wire remote trim box. The newer engine uses the two wire system with the box mounted on the back of the exhaust cover. Different systems which are not compatible. You could transfer the 85 outer exhaust cover to the 81 so that you can mount the box. The 81 block comes with the high performance rubber intake filler blocks installed. A nice feature usually only found on the 140's.

 

[Aquaduck]

Ok thank for all that very helpful

 

[toddschubert]

Re: Powerhead compatibility

My '93 88spl has the mounting taps made on the exhaust cover though not used. Check for them. Also thermostat housing differences????