Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Franki · Feb 17, 2003

Hi guys, For reasons I'd not like to explain, a mate of mine recently trashed the port cyl head.. (ok, I'll explain briefly. He was drilling out a broken water cover bolt and went right through into the combustion chamber..) Anyway, my motor is a 1972 100HP Johnson Xflow ESL10072, and I need to do something about the head now before I can get out on the water again. Now, I have a 69 evinrude 85HP here that I bought for spare parts.. According to the parts list, it has the port head part number: 314965 It looks identical externally, but I do not know if the combustion chamber is the same capacity or shape.. If it is.. I will put these heads on and get back on the water.. Unfortunatly, I can't find the part number breakdown for the 100ESL72 johnson, so I don't know if the port head has the same number. (I doubt it, but its possible..) Are these heads the same??? I am assuming they are because the evinrude lists the same head for the 85-115 HP models... so unless there was some advance made between 69 and 72 they should be the same.. Can anyone clarify that for me??? I was hoping to get out on the water this weekend, but its not looking likely anymore.. :-( regards Franki

Franki · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi again guys, Just found the paperwork on the 100HP.. The part numbers for the two heads are: Johnson 100ESL72: 316466 Evinrude 69 85HP: 314965 So the part numbers are different.. but that does not mean they are different does it??? The Johnson parts list, shows the head for the 85 and the 100 being the same head. So it "should" work.. but I'd love to hear from someone who knows more then I do. (pretty much everyone

Even the schematic diagrams of the two are identical... So now I am wondering if I should just try it and see???? Joe Reeves.. if you are here, I could really use your expertise here..

regards Franki

alcan · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi Franki Your in luck, You can indeed use your other heads.

Franki · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

ohh alcan.... You are a god....

IF you were over here, I'd invite you over with the promise of beer and steak.,,, Then you could eat, drink and help me swap heads

Should I change the starboard bank as well? or just the port?? will I lose HP by swapping or are they identical??? Thanks again. regards franki

alcan · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi Franki According to all my info they are identical. Just swap the dammaged head. There should be no power loss or gain.

Franki · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Thats great news... I will ring around today and see if I can find a head gasket for this thing... Thankyou very much, you have made my day.. Don't suppose you know the torque on the head bolts do you?? rgds Franki

alcan · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

216-240 in.-lbs.

Franki · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

I've never done this on a boat motor before.. In cars, (before the single torque gaskets came out) after a period, you backed the bolts off and retorqued them.. Is this necessary with the OB's??? and if so, what is the time frame ??? Sorry for being a pain.. just want to make sure I do it right the first time. rgds Franki

alcan · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi Franki No, there is no need to back off head bolts. They should be retorqued after being run a while and allowed to cool. Just start torquing the bolts in the center of the head first and work in a circular path to the ends. Make your first pass at @ half value. Make your second pass @ full value. I allways clean the bolts with a wire brush and chase the threads with a tap. Lightly oil bolts.

Franki · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Thanks again Mr Alcan.. I have both heads off now (the rude and the Johnny).. and you were right.. identical in all respects.. one added bonus is that on the rude heads, someone has had the water cover off and the threads were lubed... so I now have a much better head.. it also gave me a chance to clean the carbon off the piston heads... There is no lip at all on the cyl tops.. so this motor can't have done huge hours.. was alot of carbon though. (which goes to show that Johnson decarb stuff is useless, because I gave it a full decarb after the last use...) I have the rude head soaking in a tub of fuel to hopefully disolve whatever corrosion is in the water jackets.. and I will clean it up and paint with hi temp paint before putting it back on.. I should have it all back together this evening.. Thankyou so much for your help.. last night I was about ready to pull it off my boat and throw it in the nearest bin big enough to take it.. now I might actually get to go fishing this sunday..

regards Franki

alcan · Feb 17, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi Franki I have to agree with you. All that decarb juice is no magic bullit. It has how ever saved my bacon on occaission. I have used it as a soak to loosen stuck rings and restore compression. The only thing I know of that really cleans up a cylender is steam. Most of the time this does not have a good out come. Some of the old timers use to do this on purpose,(they used to do a lot of things)with positive results. There are extreme cases of build-up, both carbon and crud in the cooling system. In my expirence it is a rare to get bad enough to really cause a problem. This build up stuff is more a symptom of another problem left unattended. The stuck ring syndrom is of course from improper storage for an extended period. Usually if they are stuck by lack of oil or over heat, all the juice in the world won't help.

Franki · Feb 18, 2003

Re: Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

Hi Alcan and everyone... The head swap went flawlessly... My torgue wrench only works from upwards of 30 foot pounds.. So I may have over tightened it a tiny bit.. (I tried to estimate 20 foot pounds... (that doesn't seem like alot of tension.. I think I tightented more then that with a ring spanner and three fingers.. is that really enough to seal the gasket???) Anyway, I went to the biggest Johnyrude dealer in WA today and spoke to their OMC guy out the back.. He told me that OB's in his long term care have their heads and water covers pulled every two years or so and get a good clean and new gaskets for preventative maintenance... After the last two days.. I am inclined to agree that its a good idea.. Anyway, I'll finish with a little tip I learned the hard way.. before trying to get any possibly corroded bolt out, get out your hammer and give it 3 or 4 solid raps on the head..... do it hard, but don't put the hammer through the motor

It makes a huge difference I have discovered.. if I had done that in the first place, I would not have had to drill out studs and consequently I would not have had to swap out the head. kindest regards Franki

Do Johnson 72 100HP and evin 69 85HP have the same cyl heads?

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