100 lbs compression 1989 Evinrude 70HP worth going further?

[TwoRivers]

Don't know if someone already posted this or not, I just skimmed over it, but if your compression goes up by 10-15% with a "wet" test, you have worn piston rings. you are looking at an engine job.

Thanks for your response.
So, is what I did (spraying fogging oil in the sparkplug holes) a "wet test"".
Am I looking at an engine job?
And, what's involved with an engine job. Is it like changing rings in a dirt bike? Or is it more involved?
And, I guess we're back to the original question: Is 100 psi in each cylinder enough compression to go further with the motor.
That's what I'm trying to figure out?
And, I really appreciate all the responses.

 

[jakedaawg]

Personally, if it were my engine, I would trouble shoot the no spark situation first. If its cheap or free to get the engine to run I would then try a can of OMC engine tuner to see what that does for compression. Chances are it may help enough to have a decent running yet somewhat old engine. These motors are not worth rebuilding in my humble opinion.

With that said, it is possible that you could get a few hundred more hours out of it even if it only has 100 to 110 PSI. It is an old outboard, they only have a 30/30 warranty. 30 feet or 30 seconds, whichever comes first.

 

[TwoRivers]

Personally, if it were my engine, I would trouble shoot the no spark situation first. If its cheap or free to get the engine to run I would then try a can of OMC engine tuner to see what that does for compression. Chances are it may help enough to have a decent running yet somewhat old engine. These motors are not worth rebuilding in my humble opinion.

With that said, it is possible that you could get a few hundred more hours out of it even if it only has 100 to 110 PSI. It is an old outboard, they only have a 30/30 warranty. 30 feet or 30 seconds, whichever comes first.

Your humble opinion is respected as well as your advise.
Got it running!!!!!
Here's what happened. I took the pin connector apart and made jumpers.
Hooked up a spark detector to #1 plug and hit the key. Had spark.
#2 & #3 had spark.
Hooked up the gas, gave it some choke and it fired up and idled smoothly.
Let it run for about five minutes, making good water on the muffs, no signs of heating.
Pulled the gas connector from the motor to drain fuel from carbs & let it run out of gas.
Took the jumpers off and put pins back together.
Hooked up the gas again and it started up again but this time it didn't idle smoothly. It seems to race or hunt then slow down, seems to be missing?
Let it run for a while, it seemed to get a little better but still running rough.
Now I'm not sure if the kill switch is bad, there's a problem in the key switch or something else.
I'll hook the jumpers up again and start it up to see if it smooths out? If not I'll go from there and I'm accepting ideas?
I'll try to post a video of it running later this week.
Do I need to buy a DVA multimeter to further troubleshoot this motor?
thanks again.
It's running!!!!
rob

 

[jakedaawg]

stop. dont run engine with jumpers in place. It could overheat the key switch and cause a fire. Ill post back in a little while.

 

[jakedaawg]

Okay, instsall the lanyard. Unhook the 5 pin amphenol connector again. We are going to test the switch with an ohmmeter.

So, put one lead of your ohmmeter on a clean engine ground. Put the other on the stator side of the connector on the blk yellow wire. With key off you want continuity. with key on you want no continuity. If the Key on test shows continuity disconnect the blk yellow wire from the m terminal of the key switch. Test again and report back.

 

[TwoRivers]

stop. dont run engine with jumpers in place. It could overheat the key switch and cause a fire. Ill post back in a little while.

OOPS! Sorry about that. Won't do it again.

 

[TwoRivers]

Okay, instsall the lanyard. Unhook the 5 pin amphenol connector again. We are going to test the switch with an ohmmeter.

So, put one lead of your ohmmeter on a clean engine ground. Put the other on the stator side of the connector on the blk yellow wire. With key off you want continuity. with key on you want no continuity. If the Key on test shows continuity disconnect the blk yellow wire from the m terminal of the key switch. Test again and report back.

Will report back when I get the test done. Won't be able to get to it until Thursday.
Thanks very much.
Rob

 

[TwoRivers]

Okay, instsall the lanyard. Unhook the 5 pin amphenol connector again. We are going to test the switch with an ohmmeter.

So, put one lead of your ohmmeter on a clean engine ground. Put the other on the stator side of the connector on the blk yellow wire. With key off you want continuity. with key on you want no continuity. If the Key on test shows continuity disconnect the blk yellow wire from the m terminal of the key switch. Test again and report back.

Was supposed to work on the motor last Thursday but out of the blue my wife wanted to go boating / fishing. Took the SeaNymph down to Cheat lake in WV. Had a great day.
OK, blk/yellow wire checked good. Cleaned up some ground wires, mixed up a small batch of 100:1 premix. Hooked up the hose and fired it up. Lots of smoke. Might be because the VRO is still connected? Might still be burning off the fogging oil? Might be I originally had a tank of 50:1 hooked up when I first started it?
Seems to start and run pretty well for sitting as long as it did and the carbs and fuel filter not being touched?
I got a factory manual for it, very well written and illustrated compared to the Tohatsu and Suzuki manuals I've tried to interpret.
From what I can tell, the boat needs the transom rebuilt (orchid shaped mushroom growing out the back) and it must leak. I see where the PO dabbed some silicone based stuff around some rivets and seams (bow area).
I think the next move is to get the motor off the boat. I think it will be a good motor?
I'm not planning to get crazy with this restore. With your help I think I've determined that the motor is worth at least tuning up and cleaning up? Any comments to this regard still welcome?
If I can get the transom replaced and the leak(s) fixed that's enough for this year. I'll probably tinker some with the motor over the winter.
If any of you have any experience actually replacing a transom on this model boat, I'd love to hear from you?
I've followed many threads where the guys tear the boat apart, buy lots of new tools and fancy electronics with great pictures, then the thread dies?
I'll be opening a new thread in the Restoration section and I hope you'll add your advise.
Trying to post some pictures and I'll post a video of the motor running later.
thanks again.
rob
Click on the picture to hear the motor run, not the link below.

 

[TwoRivers]

Update to thread incase future reader is making similar considerations?
Just read on another board about there being an "Exhaust Relief Valve" on this engine and that the ERV accounts for the lower compression readings with 100 psi being ideal?
Can anybody verify this?
thanks again.
I'll post back if I find anything.
rob

 

[Barramundi NQ]

Tworivers, you did the compression test with the throttle wide open?

 

[TwoRivers]

Tworivers, you did the compression test with the throttle wide open?

Should have. But not sure now?
I'll check again but could you explain why it makes a difference?
thanks
rob