Omc 3 cylinder comparison

[phillnjack]

Also i have a head that will need skimming pretty bad, and need to know just how much can come off it to be safe.
its for a spare engine that im hoping to rebuild of the winter/spring.
if there is many mods to be done it might be a time to do it as it will need a re-bore
new pistons rods etc.
i think its possible to re-bore it, if not might be able to get it sleeved.
Im hoping the crank is ok and will get it checked out, the engine was run dry of oil by previous owner and
middle piston and bore suffered bad scores .
no 1 and no3 are not too bad,

maybe this could be a slighter more powerfull engine when re-built.?



phill

[phillnjack]

I will start a new topic on the re-build of a late 56ci and see what i can learn about that.

i am learning lots from this forum already.
its another great forum about boats and engines.




phill

[88workcar]

was that a joke about the yamaha 70 and 90 engines ?




phill

No Phil, not from me. My jokeing days are long gone. You ever make it down here bring your own gps, I'll launch the boat and give you the key.

[phillnjack]

A yamaha 70 will not touch a johnson 70 unless the yamaha is very modded.
Ive seen plenty of yamaha engines trying to keep with the johnson and evinrudes, they just
dont have it in them.
A good 60hp triple mercury 2 stroke will stay with the yamaha 70 no problem,been there and done it a good few times with same boat.
2 friends of mine both had the dellquay dory 15 footers1 with a yamaha 70 1 with a evinrude 70 and my dell quay 15 with a mercury 60.
i could stay with the yamaha ,but had no chance at all against the evinrude, he was gone and his top end was about 10mph morethan us.
maybe your 70 is realy a 90 ??????????


phill

[ima75man]

maybe you should send your mercury to hydrotec,and let them speed it up. 88workcar runs against the fastest boats in la. and texas and don't have to back up to anyone..it's what it is..

[phillnjack]

I never said the mercury 60 was slow !!!!!!!!!!!
for 60 i think it was very good for its size, and ultra reliable.

i said the mercury 60 is as fast as the yamaha 70..
i was saying the the omc 70 is the fastest of all 3.

Ive had all three engines, i know what i know due to running them myself.

The yamaha has the weakest gearcase bullet for sure,always seeing them welded up by the front ring.
evinrude i would say is far stronger and more power.
Mercury is the most reliable of the 3 engines for sure.