1975 70 Johnson Trying to get running and make it reliable

[jacobcnc]

This i my first post ive been reading alot and learning even more i bought a Starcraft Capri 15 with a 75 johnson 70 on it it was one of those "Ran last time I had it out deals".
I first could not get it to turn over new starter and battery fixed that. Now i got no fire did everything that CDI trouble shouting told me to test pointed to a bad PP3. So i got a new one of those. I ordered a factory manual in the mail by friday. So my ? is i got alot of water in my lower unit, but no metal shavings. I plan on changing the impeller just for good measure. Will the water pump kit have the gaskets i need to keep the water out of my lower unit, or is there a seperate set of gaskets i need?
And how do i pressure check the lower unit?
Thanx for all you help

 

[yjfun]

Re: 1975 70 Johnson Trying to get running and make it reliable

I'm pretty new at this so maybe someone else will have a better answer but IIRC you need the orings and seals for the prop shaft, the drive shaft and the drain and vent plugs. There are some good parts breakdowns on this site that list all these parts.

 

[jonesg]

Re: 1975 70 Johnson Trying to get running and make it reliable

90% of water in the gears is caused by re-using the seals on the drain plugs.
Buy some new seals for the drain screws and do an oil change, give it a good run and check the oil again (use new seals).
I was quoted $300 to do a gearbox seal job but a $1 seal fixed it.
Wait til you get the manual for pressure/vac tests but I would try the easy fix first.

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

I see nothing to seal the the bolts what should be on there some type of oring

 

[DargelJohn]

Re: 1975 70 Johnson Trying to get running and make it reliable

I see nothing to seal the the bolts what should be on there some type of oring

Should have a thick, plastic washer. Make sure the washer is not stuck to the housing.

FYI - You do need to buy a seperate kit to rebuild the lower unit, if necessary.

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

Thank you for quick reply have i mentioned how much this site rocks i will look for plastic washer? where do i get a new one do i have to order it? i really dont have a marina within half hour of my house. I was wondering what kind of oil to use?
Will this work http://www.cabelas.com/product/Boating/Boating-Outboards-Accessories/Oil-Lubes-Fuel-Additives%7C/pc/104794380/c/104752980/sc/104464980/Cabelas-Signature174-Lower-Unit-Lubricant/701229.uts?destination=%2Fcatalog%2Fbrowse%2Fboating-boating-outboards-accessories-oil-lubes-fuel-additives%2F_%2FN-1100542%2FNs-CATEGORY_SEQ_104464980%3FWTz_l%3DSBC%253BBRcat104512680%253Bcat104752980&WTz_l=SBC%3BBRcat104512680%3Bcat104752980%3Bcat104464980
or do i need something differnt? Sorry for all the ?s just dont wanna mess anything up.

 

[DargelJohn]

Re: 1975 70 Johnson Trying to get running and make it reliable

You will also need a pump for the bottle. http://www.boats.net/index.php?p=product&id=880011&parent=7

There are two plugs that need to be removed. The plug that you have already removed (green circle) and a second plug that is just above the cavitation plate (red circle). Drain the lube. To put in new lube: Have the motor in a vertical position.
Hook the end of the pump hose to the bottom hole and pump the lube. When you see the lube coming out of the top hole the gearcase is full. Remove the hose and quickly put in the bottom plug, then put in the upper plug.

Here is the washer. They're cheap, so I would get 10 of them to have on hand. They work on both plugs.

http://www.boats.net/parts/detail/brp/B-0311598.html

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

Thank you for all the help i got it started it fired up for about two seconds and then locked broke it lose tried it again with the same result so i guess im at a loss gonna tear it down and see what i find i have rebuilt several engines and it seames like every one that had a spun bearing. Probly just repower the boat and sell the parts as all the ignition is good and i really think so is the lower unit. you need parts let me know LOL

 

[Fisherball]

Re: 1975 70 Johnson Trying to get running and make it reliable

If you put the top plug in as soon as oil comes out that hole you will lose much less oil, it's the vent plug & no vent, no drain. If you ran motor without LU lube that could be what's locking it up.

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

i did not run the engine with out oil in lower end (read to many bad storys bout that) it had water to it the whole time. I will post with what i find when i get it a part.

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

Found the problem something fell inside the carb was sucked inside and put a whole in the intake and then was beat all to hell inside the cylinder

Thanks to all for your help looks like im gonna repower or find a new powerhead

 

[jacobcnc]

Re: 1975 70 Johnson Trying to get running and make it reliable

The real cause of the problem was that whom ever was inside the motor last forgot to tighten a rod bolt and came lose the rod hit the piston. here are some shots of the pistion.

 

[jonesg]

Re: 1975 70 Johnson Trying to get running and make it reliable

At least you got a boat and trailer out of the deal, you now know sellers lie thru their lying teeth to get rid of their junk.
Next time, compression test, check gear oil and test run.
Anything less than a complete going over is a parts engine.