70hp Carbs on a 65hp Johnson

[jay_merrill]

I have a Johnson J70ELCSA motor. which I believe is a 70hp, electric start, 20 inch shaft, 1980, production run "A" motor.

I may get around to rebuilding it someday (has very low compression on one cylinder) but the carbs were apparently rebuilt not long before I bought it as a parts motor. I have considered putting those carbs on my 1972 65hp Johnson but have not followed through because my OMC dealer seems to think I could experiece a lean mixture condition if I did so.

Frankly, I can't think of any reason why this would happen. I'm still not ready to swap the carbs between the engines because the 70hp hasn't been run in about 8 months, so the carbs would probably need to be cleaned anyway. That said, I'd love to be able to service them, to whatever degree they need to be, and put them away for a swap sometime in the future. I need to get some junk out of the carbs on my 65hp now and this made think about how nice it would be to have a "ready to go" set of carbs to put on it, so that I could rebuild the other carbs at my leisure.

Anyone have any thoughts on the compatibility issue? Has anyone ever done this?

 

[tashasdaddy]

Re: 70hp Carbs on a 65hp Johnson

it does take that long to clean and rebuild the carbs. why take a chance of screwing up a good motor.

 

[jay_merrill]

Re: 70hp Carbs on a 65hp Johnson

I'm not going to do it unless I feel certain the other carbs won't cause problems. OMC tends to use the same parts for many different motors over many years, so sometimes you can mix parts from other motors and I have done so successfully with several of the motors that I own. Hopefully, someone here will have some knowlege on this particular swap but, if not, I will just compare part numbers between the two motors to see if the carbs are the same. My guess is that they are exactly the same, with the exception of the high speed needle valves. I may be able to buy a set of the correct needle valves for a 65hp and install them in the other carbs, ending up with an identical set of carbs.

 

[Dhadley]

Re: 70hp Carbs on a 65hp Johnson

The carbs won't be exactly identical but you can use either set on either motor. Just keep the jetting in each carb as it came from the factory. Don't start swapping jets around.

 

[HighTrim]

Re: 70hp Carbs on a 65hp Johnson

The part numbers are different. There are even 2 seperate ones for your 1980 depending on the 20" shaft or the 15". Doenst mean they cant be swapped though of course.

Sorry Dhadley typing at same time.... good info to know

 

[jay_merrill]

Re: 70hp Carbs on a 65hp Johnson

Thanks, Dhadley. BTW, Port Charlotte is a beautiful place - I spent about 7 months in Northport before Charley and used to go to PC here and there. I was so impressed with it that I often thought that if I ever leave New Orleans, that's were I might go!

 

[Dhadley]

Re: 70hp Carbs on a 65hp Johnson

Hey - nothing wrong with N.O. I lived here and worked for a company there "back in the day". I always enjoyed my time there. Nort Port is just up the steet since we live in the northwest side of Port Charlotte.