plug broke off in head of Merc cruiser

[ba_50]

Re: plug broke off in head of Merc cruiser

It looks like I will take the exhaust manifold off and try to get the plugs out first. If not...


After reading the two manuals at the library, it looks more difficult than I thought.

It said to take off the exhaust manifold, doesn't look difficult unless the bolts are froze.

Then take off the valve cover, loosen the rockers, turn sideways, and take out the push rods.
Then take off the head.

This one is a 3.7 Litre 4 cylinder motor. Is there anything special about putting push rods and rockers back into place?

If I take the exhaust mainfold first, it will be easier to get at the plugs. If that doesn't work then the head will have to come off.

 

[Brenan]

Re: plug broke off in head of Merc cruiser

That happened to me a few weeks ago on my 5.0 Cobra. It appeared the major problem was a lot of gunk crusted around the spark plugs. I had never changed these either.

I soaked them with AeroKroil and removed exhaust manifolds. (Preventative)

With the exhaust manifolds removed it was easy to see all of the crap around the spark plug threads. I cleaned it all up easily with a dremel tool with ice pick diamond bit.

Once clean I pounded a SQUARE easy out and walla! it came right out. I can't remember how I got the porcelin out - I think it may have broken with the plug body. Key here was cleaning around the plug threads before taking out the plugs.

HTH Brenan

 

[cbavier]

Re: plug broke off in head of Merc cruiser

It looks like I will take the exhaust manifold off and try to get the plugs out first. If not...


After reading the two manuals at the library, it looks more difficult than I thought.

It said to take off the exhaust manifold, doesn't look difficult unless the bolts are froze.

Then take off the valve cover, loosen the rockers, turn sideways, and take out the push rods.
Then take off the head.

This one is a 3.7 Litre 4 cylinder motor. Is there anything special about putting push rods and rockers back into place?

If I take the exhaust mainfold first, it will be easier to get at the plugs. If that doesn't work then the head will have to come off.

Yes it should be much easier to get at the plugs with manifold removed and yes the push rods should go back into the same holes as removed, same if you have to remove lifters. They wear to each other. Rockers probably can only go back on the same way as they came off. I'm not sure because, I haven't done it in years, if the lifters have to come out. When you get the manifold removed you may be able to get to the plug
plug without pulling the head. That would be great.

 

[Don S]

Re: plug broke off in head of Merc cruiser

CaptJason
Let them use their "Eversieze" if they want, they WILL learn eventually.

 

[ba_50]

Re: plug broke off in head of Merc cruiser

Problem solved. I backed the Exhaust manifold out partway to get at the plug, turned the piston down to get an easy out in. Pushed the electrode in with a screwdriver. I soaked the plug in penetrating oil for a few days. A rachet attached to the easy out worked. There was some insulator material laying just inside the hole so I put some grease on the end of a metal rod with an 90 degree end on it and picked the pieces out with that. I also put a tube on the end of a vaccum cleaner that just fit inside the plug hole and used that.

Thanks. for the help.

 

[ccmarsh]

Re: plug broke off in head of Merc cruiser

We just got this boat as a project and the plugs were so thin in the middle that a slight twist broke one plug off with the bottom still in the block. There is another one that might do the same thing.

It is a 4 cylinder Merc cruiser I/O.

How are they taken out? Thanks.

I used a product called tri-lube. Sprayed the plug and 10 minutes later out it came.