140hp Evenrude Blown Head Gasket

[scuba4me]

1986 Motor I did a compression check and one cylinder the upper starboard side had 60psi. I took the head off and the gasket was a mess and had a break in the metal ring on that cylinder. The cylinder walls look ok. I cleaned up the head and ordered a couple new gaskets. My plan is to replace the one I have off and if the compression goes back to normal I was going to replace the port side one too. My question is should I do that or not? I don’t want to fix it if its not broken but if the other side looks like the one on that I just pulled then I’m worried. The compression on the other side is 130 on both.

Thanks for any pointers on this.

 

[kenmyfam]

Re: 140hp Evenrude Blown Head Gasket

Check with new gasket in place. If better consider a good decarb of the motor as well. If the same then it has cost you a gasket only. Look for scoring compared to the good cylinder in the walls. may want to leave the good side alone if all is currently well. Curiosity would make me inspect it though.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Check with new gasket in place. If better consider a good decarb of the motor as well. If the same then it has cost you a gasket only. Look for scoring compared to the good cylinder in the walls. may want to leave the good side alone if all is currently well. Curiosity would make me inspect it though.

Yes I am going to put the gasket in and check compression. The wall with the blown gasket does have a noticeable difference in a few spots but it?s not grooves is more like light high grit scratches in a few spots that do not look like they will effect anything too much. Is there anything I should do to that cylinders wall before I put the head back on is there some sort of light honing I should do without re-ringing it? I?ve seen real bad cylinder walls before. Id say this is a 2 out of 10 with 10 being the worst.

I know on car motors if you do one head you should do the other at the same time, so that?s why I?m wondering about the other side. I have 2 gaskets on the way. My thinking is just do it now before there?s an issue. The starboard side looks horribly worn from the saltwater. My gut tells me to replace the good side if the new gasket fixes the bad sides compression.

 

[HenryB]

Re: 140hp Evenrude Blown Head Gasket

Look closely for worm holing from water invasion extending inward from the water jacket side. Check both mating surfaces, cylinder and head. If some is apparent on the head surface then a fairly short money fix at a local machine shop can return the surface to new.

You may have some saltwater in the rings. I'd work the motor by hand and keep squirting a lubricant into the cylinder, and do it often as long as the head is off.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Look closely for worm holing from water invasion extending inward from the water jacket side. Check both mating surfaces, cylinder and head. If some is apparent on the head surface then a fairly short money fix at a local machine shop can return the surface to new.

The head looks great the only pitting or holes I notice are on the outside of the cylinder where the water circulates. On the top there are some pits not deep and not on on the surface of where the gasket goes. I believe I caught this early i.e. did not run it more then once when the gasket blew then ezed it in at 6mph. My guess is it was slowly going because there is some water discoloration on the inside of the head of the low compression cylinder little rust coloration but it came right off. I guess the rings could have been damaged I will know by Friday afternoon when I put the gasket on and compression check it...

 

[Joe Reeves]

Re: 140hp Evenrude Blown Head Gasket

The mating/sealing surfaces (as mentioned above) where the gasket seats..... make sure that there are no worn spots whereas water may enter the cylinders, or the combustion power enter the water passageway. Torque the head bolts 18 to 20 foot pounds in the following sequence. If no problem exists on the other bank, simply double check the torque setting.

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

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

The mating/sealing surfaces (as mentioned above) where the gasket seats..... make sure that there are no worn spots whereas water may enter the cylinders, or the combustion power enter the water passageway. Torque the head bolts 18 to 20 foot pounds in the following sequence. If no problem exists on the other bank, simply double check the torque setting.

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

Interesting thanks for that! I thought the torque order was the numbers 1-10 I was going to start with 1 and then 2 ext. It’s says nothing in the OEM manual except to torque 20-22fp in order but does not provide an order so I figured the numbers on the head were the correct order?

 

[Keepi time]

Re: 140hp Evenrude Blown Head Gasket

Make sure you have a good torque wrench when you tighten those bolts. Test it on something else to make sure it is dialed in, otherwise you could strip the threads and you don't want to go through what I just went through.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Yeah 20fp is like hand tight I have a good torque wrench I will be carful thanks for the warning. I have had the issue in reverse, so I know the repercussions.

 

[V153]

Re: 140hp Evenrude Blown Head Gasket

Per OMC you should tighten the bolts in three stages. ie. 1/3 of the torque 3 times. Joe's torque sequence (above) is as good as any.

Y'know it's not all that uncommon for those gaskets to fail from simple old age. Particularly if the motor sat for any extended period of time before being run again. In that respect I would advise you do both heads. Trust me. Little investment for a lotta peace of mind.

 

[Joe Reeves]

Re: 140hp Evenrude Blown Head Gasket

I thought the torque order was the numbers 1-10 I was going to start with 1 and then 2 ext. It’s says nothing in the OEM manual except to torque 20-22fp in order but does not provide an order so I figured the numbers on the head were the correct order?

Yea, I forgot that in later years, the factory started that numbering setup hence my mention of the sequence..

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Per OMC you should tighten the bolts in three stages. ie. 1/3 of the torque 3 times. Joe's torque sequence (above) is as good as any.

Y'know it's not all that uncommon for those gaskets to fail from simple old age. Particularly if the motor sat for any extended period of time before being run again. In that respect I would advise you do both heads. Trust me. Little investment for a lotta peace of mind.

Well that’s the case sat for 10 years before I got it and did a bunch of work to it. I’m going on the third year of using it 4-8 days a month. Didn’t do the head gaskets so if I have good psi after the first one I’m doing the other one too. Yeah your right my gut feeling is just do it too. Its just too ez not to and risk it. Plus the heads look all nice after they are cleaned up and painted

 

[Joe Reeves]

Re: 140hp Evenrude Blown Head Gasket

Yeah 20fp is like hand tight.

You must have one hellava hand!

 

[kenmyfam]

Re: 140hp Evenrude Blown Head Gasket

You must have one hellava hand!

+1 on this one !!!

 

[V153]

Re: 140hp Evenrude Blown Head Gasket

the heads look all nice after they are cleaned up and painted

Yeah, that too.

I'm in the process of rebuilding what I hope to be a badazz 140. It's had some purty extensive intake & exhaust porting done. Run 7K all day long before I got it.

Basically just tearing it down to clean'n inspect'n paint. Gonna upgrade the stator'n timer base, coils etc with some newer stuff I got layin around. Oughta be purty gnarly ...

Good luck with yours.

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

Well I replaced the gasket and that cylinder went from 60psi to 105psi. Motor seems to be running well on the ears now. The port side that I haven’t replaced yet is 130psi on the top 123psi on bottom. The bottom of the starboard side is 120psi. Still not too happy with the 105psi on the top. Should I forget about it and let it go, or should I consider taking it back off and having the head cleaned up/surfaced at a shop?

Oh by the way I did not have it documented what it was before the gasket blew but it was always the lowest one.

 

[kenmyfam]

Re: 140hp Evenrude Blown Head Gasket

Well I replaced the gasket and that cylinder went from 60psi to 105psi. Motor seems to be running well on the ears now. The port side that I haven’t replaced yet is 130psi on the top 123psi on bottom. The bottom of the starboard side is 120psi. Still not too happy with the 105psi on the top. Should I forget about it and let it go, or should I consider taking it back off and having the head cleaned up/surfaced at a shop?

Oh by the way I did not have it documented what it was before the gasket blew but it was always the lowest one.

Decarb and check compression again. Just my thoughts though.

 

[HenryB]

Re: 140hp Evenrude Blown Head Gasket

I'd pull the head.

It appears either that a leak path went unnoticed or the rings have frozen in place by rust.

If the rings are frozen or if there is a leak path at the engine block mating surface then the engine is a write off.

Cross your fingers

 

[scuba4me]

Re: 140hp Evenrude Blown Head Gasket

I'd pull the head.

It appears either that a leak path went unnoticed or the rings have frozen in place by rust.

If the rings are frozen or if there is a leak path at the engine block mating surface then the engine is a write off.

Cross your fingers

Thanks Henry,

Well I re-inspected the head before putting it back on. There were some tiny pin holes I was seeing around that port on the head. I did not think they were significant. By worm channels are these what you were referring to? They don’t seem to completely cross the aria where you can see the metal gasket ring contacts, but there are some within that aria. These are on the head NOT the block side its fine. Thanks for clarifying.

Also another probably stooped question: if I take that head back off is the gasket reusable or should I order another one now?

 

[HenryB]

Re: 140hp Evenrude Blown Head Gasket

If you were sure that the mating surface on the block is in good shape I wouldn’t be concerned with the gasket for now, take the head off and bring the piston to the top of the stroke and check for a slight bit of motion between the cylinder and piston, which would mean to me that the rings are free to move. It’s not good if the rings are locked.

Did you notice a rust ring on the cylinder wall when you first got a look at it? Saltwater did enter the cylinder and if it had enough time would have caused the ring to rust and stick to the cylinder wall. It’s good that the piston still moves.

If there is movement, and the worm grooves are on the head only, then have the head machined (my guess is a fifty buck job). The gasket is probably done for as general use but should work to do a compression test. If the cylinder comes back to life I would pull the other head and have that machined and replace both gaskets.