1979 evinrude 140.. rebuild.. help. thanks

[dom_litty09]

i have a 79 evinrude 140hp. got the bad news that it needs a rebuild.. they quoted me 2000 or i could pick it up and do it myself. it doesnt actually need a complete rebuild. all it really needs is the top starboard piston replaced (cyl 1). ive rebuilt a v6 merc before and had to pull the powerhead. will i need to pull the powerhead on this motor? or can i get to it without pulling it and pop the piston out the top? let me know. any help is appreciated. thanks, dominic.

 

[Daviet]

Re: 1979 evinrude 140.. rebuild.. help. thanks

No, the power head has to come off in order to split the crankcase to remove the rod bolts.
If you have done a merc, get the factory manual and do it yourself, you have the skills necessary.

 

[Faztbullet]

Re: 1979 evinrude 140.. rebuild.. help. thanks

it doesnt actually need a complete rebuild. all it really needs is the top starboard piston

You really dont know this is true until you measure the other 3 cylinders for wear, that may be why you got a $2000 quote which is reasonable.

 

[boobie]

Re: 1979 evinrude 140.. rebuild.. help. thanks

Agree +1 with the above.

 

[slimjohnson]

Re: 1979 evinrude 140.. rebuild.. help. thanks

Also agree with above. If your going to tear it down its not a bad idea to have all cyls measured and fix it all the first time. That being said, I repaired 1 cyl in my 140 a while back and its still running strong. All depends on your budget. Did it break the rings?

 

[dom_litty09]

Re: 1979 evinrude 140.. rebuild.. help. thanks

my budget isnt the best right now since ive been laid off for about 2 months now. otherwise id just have the shop do it. and no it didnt break the rings. i already have the manual on the motor. the shop told me that i could pry just get away with leaving the powerhead on. but wasnt sure. i didnt wanna get down to the crank case and end up having to remove the powerhead

 

[dom_litty09]

Re: 1979 evinrude 140.. rebuild.. help. thanks

they also said that the compression in the other cylinders were good. but they cant just do one since its a shop they wouldnt be able to gaurentee their work if they just replace the 1 piston

 

[daselbee]

Re: 1979 evinrude 140.. rebuild.. help. thanks

Also agree with above. If your going to tear it down its not a bad idea to have all cyls measured and fix it all the first time. That being said, I repaired 1 cyl in my 140 a while back and its still running strong. All depends on your budget. Did it break the rings?

See how common this is Slim? I did one, you did one, and now this guy.
There are a few more threads on here about the same issue; toasting one piston on these crossflows.

And, yes, you must remove the powerhead. You cannot get to the rod bolts unless you split the case.
On some loopers, you can. Not these crossflows.

 

[emdsapmgr]

Re: 1979 evinrude 140.. rebuild.. help. thanks

You'll want to address the reason for the failure during your rebuild so that it does not happen again on the new rebuild.

 

[emoney]

Re: 1979 evinrude 140.. rebuild.. help. thanks

Great point emdsapmgr. No sense in repairing the outcome of a problem without knowing the cause.

 

[dom_litty09]

Re: 1979 evinrude 140.. rebuild.. help. thanks

the reason for the piston going bad was pre-ignition of that cylinder. it was firing before the piston hit the top. after i put the new one in i am bringing it to the shop so they can set everything so it wont happen again. they said they need that piston replaced before they can do any work to it

 

[daselbee]

Re: 1979 evinrude 140.. rebuild.. help. thanks

Better check those water deflectors. Probably the cause of the whole failure.

 

[dom_litty09]

Re: 1979 evinrude 140.. rebuild.. help. thanks

ok. going to pick up the boat tomorrow then starting the tear down

 

[emdsapmgr]

Re: 1979 evinrude 140.. rebuild.. help. thanks

For sure, I'd also pull the carb apart, esp the side that feeds that bad cyl.

 

[dom_litty09]

Re: 1979 evinrude 140.. rebuild.. help. thanks

I have already went through and rebuilt the carbs about 2 weeks ago