seized 70 johnson

[farmie40]

I just bought a boat with a 76 70 hp johnson took it to lake today and it ran fine about 15 minutes then it sounded like we hit somthing and lost 1000 rpm. Didnt miss or run rough just lost rpm went and checked prop nothing. went about another 3 minutes and it quit. motor seized up. Brought it home checked cylinder walls they were fine. turned it backwards with wrench and now turns over and started. any ideas? Lower unit has oil. prop turns easy. Thanks

 

[joblo33]

Re: seized 70 johnson

Check for metal filings in the lower leg oil.<br />Eric

 

[farmie40]

Re: seized 70 johnson

I was going to take it off but I didnt know how to get the shift rod loose and I dont have a book. If the water pump was out could the motor have got hot? Thanks

 

[joblo33]

Re: seized 70 johnson

Ya, it's possible it overheated and a piston siezed but that usually leaves a mark of some kind on the cylinder wall. You might have got lucky or it might be a gearcase issue. Sorry, can't help you with the shift shaft, I don't have any Johnsons that big.<br />Eric

 

[Chinewalker]

Re: seized 70 johnson

Shift rod disconnect is underneath the bottom carb. Access the 7/16" hex head bolt with a long-reach 1/4" drive socket wrench, preferable with a u-joint just behind the socket. The bolt has a pin on the end which goes through the end of the shift rod so the bolt must come all the way out...<br /><br />Have you checked the gear oil for metal pieces??<br /><br />- Scott

 

[Silvertip]

Re: seized 70 johnson

Did you have the proper fuel/oil ratio? If you ran straight gasoline with no oil, that's why the engine seized.

 

[farmie40]

Re: seized 70 johnson

The fuel oil ratio was ok. The lower end had light oil in it so I am wondering if this was a problem with previous owner and the reason he sold it. I am going to get it apart tonite now that i know how and see what I got Thanks everybody

 

[Silvertip]

Re: seized 70 johnson

Put the shifter in neutral and try turning the prop. If it spins freely, the lower unit is probably ok and the problem is likely in the power head although the previous test does not rule out drive shaft seizure. If not, something is wrong down below.

 

[bonanzaDarryl]

Re: seized 70 johnson

To remove shift rod on my 60 johnson you had to remove starter. the rod went into a linkage you had to unscrew a bolt/ pin all the way out this released the rod..

 

[farmie40]

Re: seized 70 johnson

I got my lower drive off and took apart and it is junk. My nearest dealer,shop said the shaft was no longer available. 386122 Can anyone tell me where I could find a used or rebuilt unit? Thanks for your help. Bailey

 

[CATransplant]

Re: seized 70 johnson

Sad to hear that. Try the outboard junkyards, like tcoutboard.com. They'll have the shaft or even a whole gearcase. It won't be cheap, but it'll be there.

 

[bonanzaDarryl]

Re: seized 70 johnson

Hope you find one , I have been messing around with mine now for 2 months... lots of parts on the net, but gears alone $4-500.00 whole lower units $1200+ for rebuilt hope you make out ok... I am starting to call call grages in small towns that service lake areas cant hurt to try its only my time..

 

[mjash]

Re: seized 70 johnson

Some on ebay now!

 

[Lkr0407]

I have a 1977 Johnson Seahorse 70hp. Cranked like a top and planed off and the motor quit like you had turned the key off. Had it looked at and guy said I needed a new motor, said he couldn't spin it. Any suggestions.

 

[jbcurt00]

....Any suggestions.

Yes, 1 suggestion:

start a topic about your motor

ok, 2 suggestions:

dont post to old inactive topics, esp to ask queations about your motor.

After more then 13yrs w no new posts, this topic is now closed