TOPIC: 150hp water in cylinder

hello, i got to a point where i could try to start up the 150 that i recently got and it did start right up but all cylinders had water blowing past the spark plug threads, i am amazed it was actually running. where should i look for possible causes?
thanks

Water past the plug threads ?????

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Look again, I think you just need to replace a tired water cover gasket.

i will be able to spend more time with it tomorrow, i will take a closer look. i have family obligations calling me today.
thanks

i did start it up again today and the water is coming from around the plug holes so it is that gasket. i found a water jacket cover gasket OE 27-72142-1 and sierra 18-2573, is that one i need, i just want to make sure i order the right one. it looks like those bolts are not going to come out easily, any suggestions?
thanks

I soak em a bit before I start wrenching them plus I keep a torch with map gas on hand. If they do not turn I heat them so I do not snap em. They snap easy. If you have the early block they will be backed with nuts and are easily replaceable if snapped off but if it is the later block you have then I think they are threaded into the block so be careful and heat them well so you are not having to hack them out after the cover is taken off.
Someone suggested using rtv red on the threads when you put them back in in "minute" amounts just to coat them ever so lightly to avoid rust build up. Like the exaust cover machine bolts the tips of these are exposed to moisture so the thin film of rtv offers a little protection for the next time the bolts need to come out.

Since it looks like most of yours are out then to get by the snapped off ones a little sea foam to soak and them heat around the broken bolts with the map gas to get the cover moving off the end of the block.

WRONG GASKET!!!
You are working on the 'top cover'.

You will need the mercury marine 27-981853 or Sierra Marine (NAPA) 18-2807.
Stop breaking off the capscrews or you will have a real mess on your hands.
Disconnect the wiring harness from the lower pan.
Remove the 'U' shaped cowl under the lower pan (four phillips screws)
Remove the rear cowl support & remove the top of the front cowl support so the lower pan can sag down out of the way for the bottom capscrews on the top cover.
Then use a punch and hammer to knock the heads of the capscrews sideways a bit in as many directions as possible. This helps crush back the corrosion between the shank of the capscrews and the aluminum top cover so the capscrews can turn.
Also use propane torch heat or MAPP gas torch heat (with caution as it will get the aluminum hot enough to distort and ruin the top cover) and ever-so-gently try and get each capscrew to turn a little bit. If it is still really tight - stop and smack the head of the capscrew sideways from different directions again and then make another attempt at turning the capscrew while heat is applied.
If they simply refuse to turn for you - stop and buy a dremel with a bunch of cut-off wheels and cut the tops off the cap-screws so you can gently pry off the top cover.
Once the cover is off you will be able to apply heat to the necessary areas to remove the remaining parts of the capacrews.
If there are nuts on the ends of your cap-screws you will likely need to punch the broken cap-screws inward until their end or the nut impacts the block or they are one in a position that they will knock out all the way that way. Most on the port side will hit the block, and a couple on the starboard side will strike the fuel pump bosses, but that knocks the corrosions grip loose and you can push the broken capscrew back into the hole and ideally get a grip on the broken shank with some good vise-grip pliers and unscrew them from their nuts.
If your block does NOT have nuts - be extremely careful not to break any more and hopefully once the top cover is removed there will be enough of the shank sticking up to grip with vise-grip pliers and while heat is applied (up to about 250 degrees is best) get them to turn and remove them.
I monitor my heat with a HarborFreight laser thermometer.
Good luck and I'll keep my fingers crossed for you!

Thom

thanks for the reply. these bolts do not have nuts on them they are threaded into the block. i was able to get most of them out without breaking and i think there should be enough left of the broken ones to grab with vise grips once i get the cover off. i started to pry the cover off but decided to stop and soak it with pb blaster. the bolts that snapped have alot of rust and the cover is sticking there. maybe after soaking for a few days it will break free. what do you use to pry the cover with?

i did manage to remove the cover, unfortunately the mating surface on the #1 and #6 piston seems to corroded to make a good seal.

Your situation is certainly not ideal. Permatex make an epoxy suited for extreme water environments (it is not the standard white permatex in the red box) that I used on a repair for a merc 900 I had to replace the gasket on. The corroded area was not as bad as yours but I got it to work. Clean the metal real well as best you can. Build it up and let it dry then ad some more. Finally I took some real stiff cardboard and backed it with wax paper so the epoxy would not stick. I cut out holes for the spark plugs and used the card board to make the final mating surface. Once dried and hard I had to do some finesse work careful not to get any debris into the cylinder (leave the plug in place if you can) it worked and is still working. Do not build up the permatex to the point you are clogging off other areas of the cooling chamber just focus on the areas that require attention.
Of course the guy used the boat and motor for fishing so it was not the ultimate restore job. Motor still runs well and the repair as I said is still holding. I did take photos of the job I will have to look and see if I still have them.
Tim Calmes or Doc Frankenmerc may have a better solution for the problem but the above explanation right or wrong is how I handled it with decent results. Anything to keep a good motor running!
If I still have any of the photos I will try and post them or send me your e-mail I will send them along.

Welding using TIG ( tungsten inert gas ) creates too much heat and can lead to cracking of cylinder domes.

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So this is an ideal job for LUMIWELD wich is a brazing process with less heat.

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Of course if you take the entire motor apart you could put it on a milling machine and take a skim cut to clean things up.

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Or you could use epoxy as well.

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All choices depending on what you want here.

I just looked through my files and I do not have those pictures anymore.

so there is hope, that is good to hear. i was thinking about using epoxy i just wasn't sure if it would hold up with the expansion and contraction, so that's good to know it has worked. maybe i might run the welding idea past the maintenance guys at work and see if they would be interested. for now i have those snapped bolts to contend with. thanks for the input guys.

move forward!

jim, i found three permatex products, are any one of them the one that you used? i have permatex 84109, 84107, and 14600. 14600 has the highest heat range. also JB Weld makes a Marine Weld 8272, that has a high heat range also. both are described on their web sites.

My Bad not Permatex but Marine Tex. I am online trying to find the product. I must have been thinking to too many directions earlier this morning. Not Permatex but Marine Tex. Let me find it. I got my supply of it at Roses in Gloucester MA if I have to I will run up there to see. I wouldn't mind having a package of it on hand should the need arise.
I do apologize for sending you down the wrong trail.
Jim

I cant imagine that your cover is any better than the block as far as corrosion goes. If you are able to mill the surface you could bond a washer of the appropriate size to the milled surface in order to bring the level back up to spec. The water jacket is not under any appreciable pressure so the washer just needs to be bonded with a high temp epoxy. Once assembled nothing can go anywhere as the plug is through the washer. You would have to ensure that you replaced what you removed with the same thickness washer or the plate will never seal.

Replacing the cover may be an option over fixing the old one if it is in need of major repairs.
Neil

I probably have a good used replacement for your top cover if needed.
I try and keep any covers and plates that are still good simply because so many of them for various Mercs have gone NLA.
I have (6) huge bins full of various plates and water-jacket covers.
Please write direct if interested.
write to: frankenmerc at comcast dot net
I have successfully welded new aluminum around spark plug holes to create a good surface for the top cover to seal against.
The trick is to grind off all the dirty aluminum, using a dremel or die grinder, working until there is absolutely no trace of corrosion or dark aluminum within a 1/2" of the area to be built up.
Then explain to your welder guy the importance of welding (TIG) very slowly to avoid the dangers the professor mentioned.
I tell the welder to weld in short welds - say 10 seconds MAX - and then waiting until the aluminum block has cooled back to below 100 degrees F, before doing another weld. Patience and heat control are a must.
Then once the welding has been completed you can use an aggressive file to get down close to the intended flat surface.
Then - if you're good - you can take the surface down to a finished flat surface - but I always surrender and allow a machine shop to finish the surface on their 'resurfacer' (drawing a blank for a name) commonly used to resurface a head off an automobile.
Be prepared to have to return to the welder if voids show up in the weld once the excess has been ground off, and then of course plan on returning to have the surface smoothed out again after the follow-up welding.
Once this repair is completed and you have a cover with good raised circles around each spark plug hole you'll be good to go for a long time.
Epoxy repairs rarely last very long in this corrosive environment IMHO. I've seen many failed attempts that just add to the mess needed to be removed to gain good clean aluminum to weld to.
Thom

Thom

the top cover is in pretty good shape even around the holes that were badly corroded on the cylinders. i have decided to go with the marine tex epoxy that jim had success with. at this point in time with my daughter starting college in the fall i am taking the budget approach. anyone have any suggestions for removing the old gasket material? they are stuck on there good.
thanks

Scrape scrape scrape. Use a brass wire wheel (carefully).

hi, i got my 150 back together this weekend and everything looks good. thanks to everyone for your input.

Glad to hear you got it sorted out.
Neil