Evinrude/Johnson engine questions..

[LiLGrady17]

This board is great, I've learned so much in the few days I've been lurking about..

Just bought this boat home tonight, with this engine mounted.
1977 Johnson 85 hp Motor, model of 85EL77S on plate, On block in web 310532, cyl head 323105D, Carb 787840D.

Other motor that was included in the purchase was a 1976 Evinrude model 65693G.

Prior owner said both motors run, just not well. They didn't want to play around with the Evin & purchased the Johnson for a quick fix. He said the Johnson would bog & not rev up over 4-4500. They went thru the fuel system for a restriction, replaced the vent ect.. When I asked about compression, they both said it was good. I plan on checking it tomorrow. I'm also going to check on the depth of the stabilizer as mentioned in another post. I'll post further details as they develop.

Are these motors' parts interchangeable? Are these motors reliable when properly serviced? If compression is good, I've read on here carbs-ignition-heads can do this type of problem. For rebuilding the carbs, what kit & where from? Thanks in advance!

 

[Joe Reeves]

Re: Evinrude/Johnson engine questions..

Compression should be 100+ psi and even on all cylinders.

With spark plugs removed, the spark should jump a 7/16" gap with a strong blue lightning like flame, a real SNAP!

With the engine NOT RUNNING, but in forward gear, the timer base under the flywheel should move smoothly from its idle position to the full throttle spark advance stop screw when the throttle is advanced.

If all of ther above is as it should be, the bogging out and low full throttle rpms would be most likely due to fouled carburetors. In which case, remove, clean, and rebuild both carburetors using complete carburetor kits (about $20.00 each).

 

[LiLGrady17]

Re: Evinrude/Johnson engine questions..

Fresh fuel/oil mix, fresh battery, water & earmuffs, and it runs. I'm a boat newbie, so bear with me. I don't see much water exiting the prop. Water seems to be coming out from where the housing pivots on the bracket. Also, I dont think this engine has a water pisser. How do you know if water is circulating? I shut it down after 20-30 second because I don't want to cause any damage. What is normal for this engine? Is there a way to disable the ignition to do the compression test? My son has hit 3 parts stores, and nobody has the remote starter button.. Thanks..

 

[Lakester]

Re: Evinrude/Johnson engine questions..

Is there a way to disable the ignition to do the compression test? My son has hit 3 parts stores, and nobody has the remote starter button.. Thanks..

hello,
welcome to iboats.

u ground the plug wire connectors to block.

best to use a screw in compression tester. crank for highest reading, usually 4-5 revolutions.

no need really for a remote starter switch. crank from console.

but if need be, one can easily be made with a push button switch, 6' 12 ga wire, and a HD alligator clamp. all avail at most good auto parts stores in elec section.


regards,
lakester

 

[LiLGrady17]

Re: Evinrude/Johnson engine questions..

Thanks. Son called a buddy's dad, & got us a loaner switch unit.
I did a dry, cold compression test.
Left bank, 1-95, 2-95
right bank 3-80, 4-80.
These seem low, but the engine runs. I think I'm going to do a compression test on the other motor that came with the boat before deciding how to continue.

 

[iwombat]

Re: Evinrude/Johnson engine questions..

I had compression lower than that on my '77 V4 and it still ran good enough to get the job done. It's even on the banks, so that's good. (BTW the left bank is cyl 2&4 the right bank is cyl 1&3) When you get it going better, do a thorough decarb and I'll bet the right bank will come up some.

 

[emdsapmgr]

Re: Evinrude/Johnson engine questions..

The overboard telltale did not come out till a few years later. After starting the engine, hold your hand a few inches away from the two exhaust relief holes in the midsection just under the rear of the bottom cowling. When the engine warms up (the thermostats open) water droplets will discharge from the holes. Your hand will start to get moist, eventually water will form on your hand. This is normal operation.

 

[ezeke]

Re: Evinrude/Johnson engine questions..

Iwombat did a nice job on instructions for adding a tell-tale for your motor if you decide you want one. It's easy enough to do and the parts would run about $15.00 from a dealership. http://forums.iboats.com/showthread.php?t=222677

 

[LiLGrady17]

Re: Evinrude/Johnson engine questions..

I did the water pump & impeller. Old impelled was dry & cracking. The parts store was out of the correct # kit, so 'assembled' one from pieces off the shelf. I did the tubes & gaskets, and the inlet screen as well. Is the housing supposed to be extremely tight on the shaft? I had to pound the new one onto the shaft top. Then when the bottom hung up, I thought this can't be right,& removed it. I re-installed the old one since it seemed good & was the revised model according to Seloc. Then, as I was cleaning up my tools, I found the shaft exhaust seal.. Ugg..
I'm pretty proficient at lower unit removal now....
The engine has the water sputtering from the holes as you guys say & the water flood out of the housing has stopped, so I'd say it looks good so far..
I'm planning on doing the tell tale once I get some other things addressed..
A big thank you to everyone.. Happy boating..