Head stuck on 1970 18hp evinrude HELP

[Phillabaum]

I removed the 10 head bolts. All were very rusted in 3 of them I had to grind off the bolt heads but the head will not budge. I am getting frustrated and don't want to damage the head. Are there other bolts besides the 10 head bolts? If not then what do I do to get this head off?

 

[Phillabaum]

Re: Head stuck on 1970 18hp evinrude HELP

Well no one replied yet so I'll through out an idea to ponder. Since I took the power head off in its entirety can I split the case, pull out the crank with rods and pistons attached so I can soak the head from the inside? My goal is to re-ring anyway if the cylinders are OK. HELP HELP PLEASE

 

[ultra353]

Re: Head stuck on 1970 18hp evinrude HELP

Its probably just stuck. Take a soft mallet and tap around the outside perimeter of the head. If still won`t budge use a a gasket scraper to gently work between the head and cyl.

 

[Bob_VT]

Re: Head stuck on 1970 18hp evinrude HELP

Rubber mallet. You need to break the head gasket seal............ I have seen people use gasket cement on head gaskets and that creates a "stuck" problem. BE VERY careful that you are not tempted to try and pry it or you might damage the sealing surface.

I would advise against the gasket scraper and I would keep tapping.

If you had to grind off bolt heads then you are probably going to have a tough time.

 

[Cap'n Chaos]

Re: Head stuck on 1970 18hp evinrude HELP

There are only 10 bolts.... there is probably corrosion /crud holding the head on.

 

[boobie]

Re: Head stuck on 1970 18hp evinrude HELP

This is not a Mercury so you can't split the c/c to get the pistons. If you have 3 head bolts with the heads ground off and still stuck in the block the only thing that will help is heat.

 

[Phillabaum]

Re: Head stuck on 1970 18hp evinrude HELP

This is not a Mercury so you can't split the c/c to get the pistons. If you have 3 head bolts with the heads ground off and still stuck in the block the only thing that will help is heat.

Thanks but I thought so. DARN. I have beat on the head just to the point of damaging it. I used a utility blade and hammered it between the head and the case until the blade broke. I do not want to damage it so what would heat do and how much heat do I apply. Im I trying to burn off the gasket? This thing is really on there. Thanks for the advice so far. PS it appears that someone else has had the power head off before. Missing bolt at the exhaust and lots of silicone around the power head seal.

 

[Bosunsmate]

Re: Head stuck on 1970 18hp evinrude HELP

A wildcard, but you could replace the spark plugs and see if the compression will help loosen it

 

[bonzoscott]

Re: Head stuck on 1970 18hp evinrude HELP

Possibly, feed rope in the cylinders and torque on the fly wheel?

 

[busted-bayliner]

Re: Head stuck on 1970 18hp evinrude HELP

fill a cylinder with oil through the spark plug hole the replace spark plug get a breaker bar an turn the nut on the flywheel pressure should pop the head loose

 

[Bosunsmate]

Re: Head stuck on 1970 18hp evinrude HELP

fill a cylinder with oil through the spark plug hole the replace spark plug get a breaker bar an turn the nut on the flywheel pressure should pop the head loose

If you do this Make sure its getting near Top Dead Centre otherwise you'l be pouring oil through the intake/exhaust ports

 

[boobie]

Re: Head stuck on 1970 18hp evinrude HELP

If you use any of these tricks, which sound good, get a flywheel turner that engages with the teeth on the flywheel. Don't torque on the flywheel nut.

 

[Daviet]

Re: Head stuck on 1970 18hp evinrude HELP

I agree with boobie about using heat. You need to heat around the bolt shafts that you ground the heads off of, they are holding the head on.

 

[Phillabaum]

Re: Head stuck on 1970 18hp evinrude HELP

I agree with boobie about using heat. You need to heat around the bolt shafts that you ground the heads off of, they are holding the head on.

Thanks all the comments about using piston pressure to pop head off sounds good. I do not have the power head on the exhaust housing. and the timing plate has been removed to replace the ignition. The engine had low compression in the number 2 cyl. (60 psi) Number one was around 110 I think. Hence looking at a ring job I hope. I am going to take the power head to a friend whom has a torch (my map gas torch caught on fire due to leak) (scary) I will heat it up. I also think it is the THREE head bolts that do not expose themselves out the case that are rusted to the head. I am also soaking in penetrant. Wish me luck I will let you all know. PS GREAT SITE THANKS FOR THE HELP.

 

[oldybutagoody]

Re: Head stuck on 1970 18hp evinrude HELP

To answer one of you original questions, I'm pretty sure the pistons have to come out the top so the head does have to come off but I wouldn't assume you need new rings. Often if you have dissimilar compression readings, it's because of a blown head gasket. You'll know more when you finally get that head off. You will want to lap the head to make sure it's flat before you put it all back together. They tend to warp in the area between the cylinders. Lay a straightedge over all the surfaces of the head and block and shine a light behind it to see any high and low spots. You can lap the head yourself with a piece of glass and some sandpaper. Do a search on this forum for "lap head glass flat" and you'll find out more details. It's cheap, easy and may solve your dissimilar compression problem.
Here's a link to one post for lapping info.
http://forums.iboats.com/showthread.php?t=534366&highlight=glass+lap+head+flat

 

[Phillabaum]

Re: Head stuck on 1970 18hp evinrude HELP

You will want to lap the head to make sure it's flat before you put it all back together. They tend to warp in the area between the cylinders. Lay a straightedge over all the surfaces of the head and block and shine a light behind it to see any high and low spots. You can lap the head yourself with a piece of glass and some sandpaper. Do a search on this forum for "lap head glass flat" and you'll find out more details. It's cheap, easy and may solve your dissimilar compression problem.
Here's a link to one post for lapping info.
http://forums.iboats.com/showthread.php?t=534366&highlight=glass+lap+head+flat[/QUOTE]

Thanks I will look into that. I was going to get my brother in law with a milling machine to mill just enough to make flat if needed. THE HEAD IS OFF. I had to do ALL the bad things to get it off. The three bolts that do not expose out the case were rusted and pitted to the head. Had to drill out the best I could (drill drifting into the head area). Soaked with penetrant and LOTS of heat. Used a thin blade to cut loose the gasket, and YES pry the head off. Hammering did not do it. TOOK THREE DAYS. No apparant damage to gasket surfaces thank god. So
1. remove the three head bolts
2. remove the four exhaust cover bolts (also broke)
3. mill the head and case surface (careful not to change compression)
4. hone the cylinders.
5. order parts.
Thanks for everyones input. Look for new posts of progress

 

[oldybutagoody]

Re: Head stuck on 1970 18hp evinrude HELP

Did the head gasket have any holes in it? What was your compression before removing the head? If you crack open the block to change the rings you'll need to replace the upper and lower seals and use some 3m 847 on the block halves when you button it back up. Probably too late now but an impact screwdriver really is a necessity to remove the exhaust cover bolts.

 

[AlTn]

Re: Head stuck on 1970 18hp evinrude HELP

3M 847 might not be a good choice for bonding the cranckcase halves together...Gelseal is still the recommended one and is available

 

[oldybutagoody]

Re: Head stuck on 1970 18hp evinrude HELP

AITn, I used the 3M 847 on my Fastwin. Am I going to regret it?

3M 847 might not be a good choice for bonding the cranckcase halves together...Gelseal is still the recommended one and is available

 

[AlTn]

Re: Head stuck on 1970 18hp evinrude HELP

I emailed 3M about using 847 in this application and they replied it was "NOT" recommended for bonding the crankcase halves in 2 stroke motors....I dunno oldy from personal experience as I've never tried it