Not my day for compression checks

[mrbarth]

Hi there,<br /><br />seems not to be my day for a compression check.<br />Got a problem on Sunday, engine (1990 90 HP OMC)<br />lost power partly and died on idle, hard to start.<br /><br />Tried to check compression today, pulled spark plugs, checked the first 3 cyls. While unscrewing the gauge from cyl 3, I realized that the adapter ring was still in the threading, partway in and now didnt came back out. <br />(The previous owner had damaged the threading and had a slightly wider one drilled in the head with an "adapter" ring to fit the normal spark plug)<br /><br />Any idea how I can get this ring out without pulling the head ???? <br /><br />Thanks

 

[Dhadley]

Re: Not my day for compression checks

Did the compression gauge adaptor come out or is it stuck?

 

[mrbarth]

Re: Not my day for compression checks

Thanks for the reply.<br /><br />The gauge adaptor came out fine.<br /><br />I can as well screw it in again. I can even screw in a sparkpluck, but only the first 2 or 3 threads at the front are engaging.<br /><br />It looks as if the gauge adaptor went into the<br />spark plug adaptor ring maybe half of the<br />way, and then the adaptor ring started to turn with the gauge adaptor, thereby screwing it in.<br /><br />The sparkplug adaptor ring is so far in, that the cyl would hit it lightly if on top

 

[mrbarth]

Re: Not my day for compression checks

An idea ?<br /><br />I just looked thru the SELOC manual.<br />It looks as if I just can take of the cylinder head cover. From the drawing p3-31 it looks as if the<br />plug threadings are in that. Would cost me a new<br />head casket ?

 

[rickdb1boat]

Re: Not my day for compression checks

Pull the cover off and helicoil it if needed....

 

[ezeke]

Re: Not my day for compression checks

Question for Dhadley re: this problem. Will red Loc-Tite hold the Heli-Coil on a head, or will the heat break it down?

 

[Dhadley]

Re: Not my day for compression checks

I'd go ahead and finish the compression test. That last cylinder may determine where we go from here.

 

[mrbarth]

Re: Not my day for compression checks

Thanks guys,<br /><br />at least now I know how these things are called.<br />The head was is already helicoiled for one spark plug and the helicoil is too far inside and doesn't come out.<br /><br />I tried some other stuff like a wood stick or rubber to no avail.<br /><br />I pulled the head and now can work from the other side to get it either completely out or back again.<br /><br />Have to stop as the no-see-ums start to eat me alive. And I have to wait for new caskets anyway.<br /><br />Dhadley, I couldnt do the compression test on the last cylinder, as the helicoil in the other one was so far in, it would have hit the piston.<br /><br />Thanks again.<br /><br />Any secret tips on getting the head on again smoothly would be appreciated. Do I need a buy a torque key ?

 

[mrbarth]

Re: Not my day for compression checks

One additional thing,<br /><br />just checked through this site. Of course I need a torque wrench. <br /><br />I find the head gasket here at iboats for my engine<br />with nr. 18-2956(1), but not the head cover gasket ?<br />Any hints who is selling this ? Cant find it on <br />vintageoutboards etc. Is it ususally included in a set ? But I think I can find that myself.<br /><br />Thanks again for your time and advice

 

[wilde1j]

Re: Not my day for compression checks

Most BRP dealers would either have the cover gasket or could order it for you.

 

[alden135]

Re: Not my day for compression checks

Why not just replace the head since it's already off?

 

[mrbarth]

Re: Not my day for compression checks

thanks guys,<br /><br />after the head came off, I saw that the last cylinder (the one I had not checked yet), has a lot of small dents and looks quite rocky on top. Same for the head. A tip from the dealer to check with a feeler gage showed that the rings are gone for a little over 1/2 inch on that piston, and the chips had hammered around a while. <br />Looks like I have to look for a place where they take scrap metal. Or use it as anchor-

 

[reeldutch]

Re: Not my day for compression checks

or rebuild it???

 

[mrbarth]

Re: Not my day for compression checks

reeldutch,<br />I learned a lot here on this forum, got the engine running, trim/tilt repaired, carbs set up etc,<br />but rebuilding the powerhead is a job I don't think is in my scope.<br /><br />The engine is 1990. I bought the whole 24 feet pontoon 2 years ago for 4K and it was in bad shape. (my first boat )<br />So I'm not sure about the lower unit, and what I'm reading in the seloc manual, there can be a lot of problems on that way as well.<br /><br />Otherwise I might think to buy a rebuilt head.<br />But as said, might be a hole without a bottom.<br /><br />Thanks

 

[mrbarth]

Re: Not my day for compression checks

reeldutch<br /><br />in your opinion, how long would an average experienced "craftsman" need to rebuild a 90HP Johnson (doing it the first time) ?, just a ball park ? And in some other post rodbolt said it does not make sense to only do the repair if you that far down in the engine, but replace other "used" parts as well, so how much money are we talking, also a ball park would be nice ?