Things are Getting Wierd - 1976 15 Hp Evinrude

[OptsyEagle]

Ok, so I am trying to get a non-running 1976 15Hp Evinrude going. When I first obtained it, it had good compression (100psi on both cylinders) but no spark on either cylinder. I popped the flywheel and changed the points and set them to 0.020" and replaced both condensers. Presto, great spark with both, jumping about 3/8" gaps.

I fired it up and had a difficult time getting it to continue to idle, so I decided to clean and rebuild the carb. I also changed the water pump and since I think it had been in salt water before, I changed the T-stat (it was all corroded and the seal was gone) and replaced the water jacket gasket.

I fired it up in the barrel and it seemed to run great. Before I patted myself on the back, I wanted to see if both cylinders were running so I pulled each plug boot, one at a time. Well, when I pulled the bottom cylinder plug boot, nothing changed but when I pulled the top cylinder plug boot, it died. This told me that I had only one cylinder running. I then decided to switch the plug boots to see if the problem moved to the other cylinder. When I just switched the boots, I could not get it to start. When I switched just the coil connector clips, I could not get it to start. But, when I switched both the coil clips and the coil plug boots, it started. But guess what?, only the top cylinder is still running. I thought the problem would switch to the top cylinder and get the bottom running, but the top cylinder was still my only running cylinder. I should add that I am using two new Sierra secondary coils at the time. I changed them, not because they were defective, but because they were very corroded and had some cracks in them. From my experiment above, It would appear that they are both working OK with continuity measuring in at about 14.7 K Ohms each.

What's going on here? When I pulled the plugs (they were brand new gapped at 0.030" when I started this process) the top one had a little bit of oil residue, but the bottom one was still pretty shiny with no oil on it at all. The center electrode gave evidence of firing but the white insulation was very clean as opposed to the top plug had some slight brown dis-coloration.

I am thinking that perhaps water might be getting into my bottom cylinder but my question would be, would that keep it from running and could it have good compression numbers with a defective head gasket (assuming that is where it is coming from). My other thought would be reed valves, but I know very little about them.

Please help with any suggestions and advice? I am into weird territory here.

 

[Daviet]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Swap the plugs and see if the lower cylinder washes the the dirty plug clean, sign of water getting into the lower cylinder, maybe head gasket.
Maybe a lower crankshaft seal, causing a lean condition.

 

[OptsyEagle]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Thanks, that's a good idea. I will swap the plugs and see if I can clean a dirty one, so to speak.

Would there be any test to check for a bad reed or a test to check for a bad crankshaft seal, to verify or support the problem, before I tear down the engine?

 

[bktheking]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Here was my issue, very similar, same motor, same issue:

http://forums.iboats.com/showthread.php?t=384221&highlight=evinrude+15

I think you may have to tear into it to find out what is going on.

 

[OptsyEagle]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Thanks BK, that was interesting.

On your motor, did you then have two problems? Water in the cylinder (probably coming in from the head gasket) and a plastic tie in your reeds. The reason I ask, is that I am assuming that a plastic tie in your reeds could not have been the cause of water in the cylinder, but perhaps I am mistaken.

 

[bktheking]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

No, I believe there were 2 factors, 1- the headgasket was questionable and the water tube grommet was totally gone. That would have lead to water in the cylinder.

The second strange part was the sound. With the powerhead off and the plugs out I could here the distinct sucking sound in the top cylinder, meaning the reeds were opening and closing, the bottom made no sound which was due to the zip tie being stuck in the bottom reed. Pull your plugs out and listen for it, just turning the flywheel by hand should make the noise, the sound should sound like a twin instead of a single cylinder.

 

[OptsyEagle]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Thanks BK. The water tube grommet provides an interesting clue. I found some black rubber material in the water exit cavity of the skeg. It was chewed up a little and more chewed up as I pulled it though the little holes of that cavity.

Could a missing water tube grommet make its way to the water exit cavity of the motor, and if so, I assume this could send water into the bottom cylinder?

 

[wilde1j]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

The rubber is more likely a piece of impeller.

 

[bktheking]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

For sure it could but that would be a guess, no way of really knowing without pulling the powerhead. If the grommet has never been replaced i'm willing to bet that it's destroyed, every 70's motor i've pulled apart 9.9 or 15 needed a new grommet.

 

[OptsyEagle]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

This weekend I plan to pop the cylinder head and take a good look at the gasket, cylinder and pistons. I suspect water is getting into the bottom cylinder. If I get lucky and it is only a bad head gasket, does anyone have any suggestions for getting the water out of there before I put on a new head gasket and torque down the cover?

 

[bktheking]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

Blow out any water with a blow gun off of a compressor.

 

[OptsyEagle]

Re: Things are Getting Wierd - 1976 15 Hp Evinrude

What about adding a little bit of denatured alcohol to the wet cylinder to kind of sop up the water that might be in the crankcase? Is there anything in there that might not like a ounce or two of alcohol?