Next victim 1998, Evinrude 150, Head O rings,J150EXECD

[pastorbud]

I found an old Storm window in the shed, and used that. But my compression tester seems to be faulty. See the video.

 

[pastorbud]

This may sound like a strange question, but do those O-rings around the cylinder have any effect on compression, or are they just for keeping water out from the water jacket? I’ve never worked on a Head that has that kind of O ring in it, and I don’t understand how a rubber O-ring could stand up to that kind of heat and pressure.

 

[Faztbullet]

Those seal the head to block doing both compression and water sealing...by the way I have only seen 2 o-rings on these models fail.

 

[pastorbud]

Those seal the head to block doing both compression and water sealing...by the way I have only seen 2 o-rings on these models fail.

Wow!

 

[oldboat1]

I But my compression tester seems to be faulty. See the video.

Speaking of 0-rings, isn't that about the third tester you used there, Pastor? I'm thinking you do not have it screwed in snug enough. I don't know if it's correct, but I get mine started (to avoid cross threading), then screw it in holding the rubber hose -- snug, but just hand tightened. I've never had it leak down (press the release to reset it to 0.)

 

[oldboat1]

I haven't tried this, but maybe some smoke or steam around the head and compression tester would give a clue as to a leak location.

 

[pastorbud]

Speaking of 0-rings, isn't that about the third tester you used there, Pastor? I'm thinking you do not have it screwed in snug enough. I don't know if it's correct, but I get mine started (to avoid cross threading), then screw it in holding the rubber hose -- snug, but just hand tightened. I've never had it leak down (press the release to reset it to 0.)

It’s the same loan-a-tool from last episode. I wanted to try it on another head to see if it did the same thing, before I brought it back and reported it defective.

The Bosch pressure tester I bought does the same thing.

A Snap-On tester I borrowed from a friend did not leak down (in a prior test) but I already returned it to the owner.

Ima try a different loan-a-tool tomorrow!

 

[Faztbullet]

If you can get 90-95psi each cylinder your good

 

[pastorbud]

I haven't tried this, but maybe some smoke or steam around the head and compression tester would give a clue as to a leak location.

Well I bought another compression tester, and got a good steady reading. Just before I threw the old one away, I took a flashlight and looked down inside the quick release connector, and saw that a little O-ring down in there had been dislodged. I was able to take it partly apart and put the O ring back in place, and now I have two working compression testers.

these readings are on the “good“ side of the motor. I put the other head back on the bad side, just to keep it covered and find out what was going on with my testers. I’m still cleaning up the bad head. It was pitted around the place that matches the #1 cylinder, So it has been a lot of work.

The pits have been smoothed out enough that you really can’t feel them, but they show up as tiny black dots. I don’t know whether to keep sanding or not. I’d like it best if I could get them gone altogether, But I wonder if that’s necessary.

 

[pastorbud]

Those seal the head to block doing both compression and water sealing...by the way I have only seen 2 o-rings on these models fail.

I think this problem started with a broken thermostat spring and an old seal. I had a lot of corrosion and gunk where the thermostat seal meets the block and the spring above the thermostat seal was broken.

Water got in and eventually the problem spread to the #1 cylinder.

It has cleaned up pretty good, (The picture is from before I cleaned it up) but there is moderate pitting around the place where the thermostat seats on the block.

I am not sure what can be done about that pitting.

 

[racerone]

Your local machine shop will have some hand tools ( end mills / reamers ) to clean that up.

 

[pastorbud]

I’ll put another picture up. Now that it’s cleaned up, I can see that it’s really very minor pitting.

I see one thread here where a guy got away with using JB Weld...on a pitted cylinder sleeve!

I do know not to get anything on the O rings but lube.

 

[pastorbud]

I forgot how hard it is to post links here.

 

[pastorbud]

Here’s a screenshot of the thread.

 

[Faztbullet]

Just put a thin circular bead of silicon around it as the seal for the t-stat is in the head. The pits in head are 100% are they are porosity pits from the aluminum casting process...they wont hurt a thing as the will eventually fill in with carbon.(the black dots you are seeing now)

 

[pastorbud]

Just put a thin circular bead of silicon around it as the seal for the t-stat is in the head. The pits in head are 100% are they are porosity pits from the aluminum casting process...they wont hurt a thing as the will eventually fill in with carbon.(the black dots you are seeing now)

I’ve got some close-ups of the head. If I understand what you’re saying about the porosity pits, those are going to stay there no matter how much I sand.

I have used 150 grit sandpaper, followed by 220 grit sandpaper, and next I will use crocus cloth.

The angle of the work light I am using makes the sanding marks look much more pronounced than they are. You can’t even feel them with your finger.

I think I’m almost done!

 

[Faztbullet]

Put it together !!!!

 

[Chris1956]

Bud, for the future, you can buy some blue dye (Steel Blue Layout Fluid) that is painted on the head, before you sand it down. As you sand the head, the remaining blue shows the warpage. When the blue is gone, the head is flat or close to it.

Machine shops used the stuff in the 60's, but have better methods now. Us amateurs can still benefit.

 

[pastorbud]

Bud, for the future, you can buy some blue dye (Steel Blue Layout Fluid) that is painted on the head, before you sand it down. As you sand the head, the remaining blue shows the warpage. When the blue is gone, the head is flat or close to it.

Machine shops used the stuff in the 60's, but have better methods now. Us amateurs can still benefit.

Cool!

 

[pastorbud]

I've developed a very special relationship with sandpaper......