overheated

[badride]

Well...I did it. 1978 35hp Johnson. I have had the motor for a couple of months and it seemed to have good pressure. It ran like a top. Had new coils and some other ignition parts.<br /><br />It just quit putting out water while on my maiden voyage of a weeklong beach trip. I was in an inlet with a quick outgoing tide. It ran for about 3 minutes before I could get to shore. Melted the coils somewhat. Melted the water outlet. Melted the water pump housing. Discolored the paint on the back of the engine.<br /><br /> It used to start literally on the first hit. Now it is a hard starter. It will start and seems that it wants to run, but wull not hold an idle. It does have a new water pump(now...I know...I'm a dumb***).<br /><br />Where do I start. Am I done? Is there a way to test the coils? I don't want to put more money in the motor than it is worth. Could it have gotten hot enough to screw up my compression? Rookie. Need help. thanks for any replys.

 

[Yepblaze]

Re: overheated

Find yourself a compression tester. Unscrew the plugs and test one at a time while cranking it over till the needle stops climbing. <br /><br />I would suspect the overheat condition might have done something to the compression. I would hope it would read over 100-120 psi or better. Also We would like to see a variation of less than 10-15% between the two cylinders.<br /><br />Let us know how the compression check goes.

 

[badride]

Re: overheated

Thanks. Will do. I'll be back.

 

[badride]

Re: overheated

60 psi in both.

What to do?

 

[badride]

Re: overheated

bttt

 

[badride]

Re: overheated

Yepblaze?...anybody?

 

[JB]

Re: overheated

Um, er, ah, Mr. Badride. Well, er, there is hope. But not much.

<br /><br />If you are fortunate, the cylinder walls are not destroyed. Remove the cylinder head and look. No grooves? No galling? Good. You may get by with new rings and maybe pistons. <br /><br />I think you are past the point of help online, but let us know what you see in there.<br /><br />Regrets.<br />JB

 

[badride]

Re: overheated

Thanks. Roger.

 

[badride]

Re: overheated

Hey guys. Good news...I guess. The walls of the cylinders are as smooth as silk. No scratches at all. The head gasket was toast. Between the cylinders there was nothing but the metal ring surrounding each cylinder...no gasket material at all. Could they have been leaking into one another? Would this explain the equal psi(literally to the pound?)<br /><br />What next? Don't give up on me

 

[JB]

Re: overheated

You are really living right, Badride. Replace the head gasket, after ensuring that the head isn't warped. <br /><br />Need a piece of plate glass larger than the head and a full sheet of 400 to 600 wet-or-dry carborundum paper. Lay the paper on the glass, lube with water, press gently down on head and use gentle rotary motion. Check that head surface is uniformly "polished". If not, get it resurfaced at a machine shop. Then re-install and good luck.<br />JB

 

[badride]

Re: overheated

That is cool! Thanks. I have the plate glass handy and will find the paper. I will post the results of your goodwill. 120 x 120

OK...I'll settle for 100 x 100.<br /><br />Thanks again.

 

[badride]

Re: overheated

All right. The head is not warped. New head gasket installed. I have 90 in both stone cold. Should I expect to have better at operating temp?. Is that good enough? Should I proceed?

 

[JB]

Re: overheated

Still low, Badride, but not nearly as low as it was. I don't think you have anything to lose by firing her up and putting a load on her.. . . .properly cooled, of course.<br /><br />Good luck.<br />JB

 

[badride]

Re: overheated

".. . . .properly cooled, of course."<br /><br />Indeed. <br /><br />Thanks for all the help.