Johnson 70HP 1981? j70ELCIH? Compression test

[ryan_the_sparky]

Hi from new zealand !

I am looking at buying an 70HPjohnson outboard and boat. engine cowling says seahorse on it


Model # J70FLCIM
serial # A67731
Name plate is really hard to read.

I dont think this model exists so i think it might be either A J70ELCIM or J70ELCIH ??????? i dont know engine year.

I gave it a compression test and 2 cylinders had 115psi and 110 psi on the other one.

Can you please tell me
1) what model its likely to be
2) what year
3) what factory psi values should be
4)if these psi values im getting on cylinders are expectable


Thanks so much !!!

 

[5150abf]

Re: Johnson 70HP 1981? j70ELCIH? Compression test

Yup, it is an '81, there really isn't a model, it is just an '81 70 Evinrude.

There are no "factory" compression numbers btu yours sounds pretty decent, if they were taken cold they will jump quite a but when the engine is hot.

Better to do a comp test with the engine hot so everything is sealed well.

I have an 81 50 and cold comp is about 115 but that goes up to 135 when it is hot, generally anything over 100 is considered good.

Get into the FAQs and search DECARB and do that usually helps.

 

[ryan_the_sparky]

Re: Johnson 70HP 1981? j70ELCIH? Compression test

o cool thanks man. ran the engine for 2 mins so head was warmish. did not ground the plugs at all, only put on full throttle and cranked engine.

kinda stupid question but can much go wrong on these engines- like are they pretty reliable and are parts still reasonably priced and available?

in my mind i would typically never buy a engine anywhere near this old age, but newer ones are so damm expensive down here...

what do people think of these engines?

 

[ryan_the_sparky]

Re: Johnson 70HP 1981? j70ELCIH? Compression test

Also this decarb thing you were talking about - dont think we have it in new Zealand, but does combustion chamber clearer and carb cleaner do the same magic to the motor ?

 

[tashasdaddy]

Re: Johnson 70HP 1981? j70ELCIH? Compression test

carb cleaner has no oil, not recommended. keep the carbs clean, it has 3 carbs, one for each cylinder, if one carb get contaminated, you will have no lubrication to that cylinder, thus, BOOM.

also good water pump is necessary, replace impeller every 2 years.