1995 35hp Johnson 2 cyl.

[Harker]

This is on the AML35D....I thought the plugs had been steam cleaned so I went and bought a new compression gauge today. The motor is in a shop at about 65 degrees, I took out both sparkplugs, gave it full throttle and pulled till the gauge wouldn't go higher. Top cyl. was 100 lbs and bottom was 95 lbs. I don't have 25 hours on this motor since I rebuilt it with new pistons, rings and a brand new block.Unfortunately, I couldn't find my old compression tester before I started break in for a baseline. I was expecting higher compression. I haven't retorqued the head bolts yet. Would you expect any compression with a blown head gasket? Thanks for any info.

 

[ezeke]

Re: 1995 35hp Johnson 2 cyl.

If you think you might have a bad head gasket, which white steam, clean plugs and maybe some water on the plugs would have indicated, you should go on and put the new gasket in and retorque your cylinder head. The last thing you want is the water hanging around in there on your rings and bearings.

I don't know what the difference is with those engines, but they are supposed to be ported to drain quickly in the event they are submerged. That would have to make some difference in the compression.

 

[Harker]

Re: 1995 35hp Johnson 2 cyl.

Ezeke, when I rebuilt it, I found a NIB shortblock on ebay for less than it would have cost me to re-bore the original so all that dewatering stuff is GONE. Guess I will just get a new gasket and put it on..easy-peasey....

 

[JB]

Re: 1995 35hp Johnson 2 cyl.

Those numbers are fine for a rope start new engine not broken in, Harker.

 

[Harker]

Re: 1995 35hp Johnson 2 cyl.

Thanks JB, I am still not positive that there is water intrusion. I'll retorque the head tomorrow and see if the numbers go up at all. I have Boyeson reeds in it, would that make the psi different than stock reeds?

 

[JB]

Re: 1995 35hp Johnson 2 cyl.

No. The reeds have nothing to do with cylinder compression.

 

[Harker]

Re: 1995 35hp Johnson 2 cyl.

I've heard two different stories on retorqueing head bolts. One is to just set the wrench and torque, the other is to loosen the bolts and then retorque. What is the consensus here? I'm leaning towards the loosening method...Thanks.

 

[HighTrim]

Re: 1995 35hp Johnson 2 cyl.

There is a sequence you should use, starting in the center, then working in a circular fashion outwards. Just imagine the numbers to be bolts.




9................10
5................6
1................2
4................3
8................7

 

[Harker]

Re: 1995 35hp Johnson 2 cyl.

Yep, had my manual for the sequence. I set my torque wrench at 240inlbs and tightened them up. Some of them seemed pretty loose.Compression actually went down a smidge. I have a question about the water diverters in the block. I think I will pull them out and replace them when I change the gasket. Do you guys just use hose for them or do I have to try and find the OEM parts? Are they supposed to bottom out in their channels? It seems like when I put the thing back together that I could push them down in the block below flush with the top of the cylinder. This motor runs super cool and I just started thinking about those...they were out of the military block so was wondering if mybe they had been shortened for some reason.

 

[Harker]

Re: 1995 35hp Johnson 2 cyl.

Popped the head off and can't see where anything went through the gasket. I'll get a new one coming anyway. When I loosened the head, water came out between the block and head, I thought outboards were supposed to drain out? It hasn't been in the water for two weeks and it has been in the down position.

 

[Kyshorthair]

Re: 1995 35hp Johnson 2 cyl.

I am having a similar problem with my 99 25hp Johnson. Did the gasket fix yours? Thanks.