1955 25 horse Head Gasket Bad?

[55Crestliner]

I finally got my "new to me" motor running tonight, (after I remembered to close the pressure tank cap, what an idiot ).<br /><br />I did a de-carb, but noticed it won't stop smoking (white smoke). The odor of the de-carb is finally gone. Then I noticed there is water coming from the bottom pan. There is a 1/4 inch hole in the pan, and water is STREAMING out of it. I have to assume this is a hole in the head gasket, because the stream lines up with the gasket surface. Why would they have put a hole right there? Is this a common place for a gasket to go bad? I also notice that there is a long dent in the leg, right where the hole is, almost to suggest you would put a screw driver up there for something. Any ideas what's going on here?<br /><br />I took a digi pic of the water, but I bet Paul or someone else already knows what's going on without a picture <br /><br />BTW, compression is 80psi in both.<br /><br />Motor is running relatively good, but doesn't seem to want to go as slow as the 10 or 18 I have - I bet that's normal anyway - not a big deal.

 

[Paul Moir]

Re: 1955 25 horse Head Gasket Bad?

Right at the very bottom of the head is where the block's water outlet is. Immediately before it goes out there, the water runs down the "pipe" cast into the head. The mating surface is pretty thin between the block & head there, but I don't think I've ever seen a leak at that point. There shouldn't be much pressure there since it's open straight into the water outlet on the midsection, but that point is a bit of a constriction. If there's a lot of water coming out, then there should be a rather substantial hole.<br /><br />Try to upgrade your suspicions to certainty by sliding some paper or something between the head and the pan. Sierra head gasket 18-3865 ought to fit your engine, although Sierra doesn't seem to think so. <br /><br />EDIT: Oh, there's also a core plug at both ends of the "pipe" in the head. It may have popped out of the lower end of the head if water gets trapped and frozen in there (say, from storing the engine on it's back). That would open about a 1/2" hole into the cooling passages.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

I'm a bit confused. You're saying water is supposed to be coming out of there? <br /><br />What would I be looking for by puting a piece of paper between the head and pan?<br /><br />(as always, thanks for your quick replies!)

 

[Paul Moir]

Re: 1955 25 horse Head Gasket Bad?

No, water shouldn't be coming from there. Your leak appears to be near where the water exits the block (normally), but not the outboard. Normally it comes out the large hole on the back of the mid-section. <br /><br />If it's leaking just a bit, a piece of cardboard or paper can be used to identify exactly where the leak is. Just put it in place, run the engine a bit, and check for water marks. If you've got a real gusher, then you'll just end up with a mess.<br /><br />Is there any hope of determining if that bottom core plug is in place? It should look just like the one on the top of the head.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

Yep, it's a real gusher, it's just about the amount of water a modern motor puts out from what they call a "pee hole" (I think that's the term).<br /><br />I'll have to take the pan off, see what's going on.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

As can be seen here, the water is coming from a 1/4 inch hole in the block, not the head, or the gasket. My 10 and 18 horse do not have this hole. This hole has no threads in it, doesn't appear to be missing a plug of any kind.<br />

 

[Chinewalker]

Re: 1955 25 horse Head Gasket Bad?

There should be a bolt in there. It is one of the powerhead bolts, so there aren't any threads in the lower unit portion, but there should be some further up in the hole. Get a bolt that matches one of the other bolts nearby...<br />- Scott

 

[Chinewalker]

Re: 1955 25 horse Head Gasket Bad?

To clarify things a bit, the hole leads up into the powerhead waterjacked. It is normally plugged by the bolt and isn't a problem. Running it like that may be a problem as it may prevent water from filling the rest of the jacket cavity by allowing to much water to exit the block.<br /><br />The bolt should be a 1/4"x20tpi. Not sure on the lenght off the top of my head, so match it with an existing bolt...<br />- Scott

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

Ah, thank you so much, I'll try it out!<br /><br />At 80 psi in both cylinder, would someone more experienced than I automatically put in a new head gasket now that the bottom pan is off? <br />(not that it's hard to take off.)<br /><br />btw, above I mentioned that the white smoke hadn't stopped, well, it has gone way down, I think I still had/have a little decarb in there.

 

[Paul Moir]

Re: 1955 25 horse Head Gasket Bad?

Ah, a picture is worth 1000 words! Chinewalker is right on the money. Coat that bolt in sealant when you put it in, so it'll come out next time. <br /><br />80 psi would seem about right to me - the 25hp was a pretty low compression engine when it was new. Don't bother popping the head off. There's no point really. <br /><br />That bolt is kind of a pain to get at. I think it uses a reduced head on some or all models so finding a replacement that will work might be a bit of a pain. You may have to steal one of the others. An alternative is to use a socket head cap screw (allen drive).<br /> <br />The white smoke may indicate one or both cylinders are running a little rich. But I wouldn't worry much until you've got an on-the-water adjustment and hard run. Click my man-next-to-house icon for a comparision running engine (on a winter day).<br /><br />EDIT: Oh, and the bolt is 1" and 1/8 long (in classic J/E). You can subsitute 1" and 1/4 there no problem.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

Again, thanks so much to both of you for your help. I have no idea how I ever would have found this out without this forum.<br /><br />I took a look at your picture, (cool looking motor!) That smoke is about what mine is starting to look like, just like my other 2. I agree, it just needs a good on lake test.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

Well, it wasn't as simple as just puting in another bolt. It never is, is it?<br /><br />There was a busted off bolt in that hole. I knew I couldn't deal with it with the block on, so now I know what the bottom of the block looks like! A previous owner or mechanic started to drill out that bolt, and I'm guessing tried to use an easy out but gave up. Bolt was still in there with a hole all the way through (explains the water coming out). So I drilled it out, retapped, and it's good as new. (same size threads).<br /><br />Between the block and the leg there are 2 fiber gaskets, separated by a stainless steel plate.<br /><br />So, I went to SeaWay, and according to their books for my motor, it only asked for one fiber gasket. We finally found the stainless gasket listed for a '56 30 horse. <br /><br />So, here's the question - why did they change to adding the stainless gasket? It seems more restrictive to the exhaust, but I'm guessing they were smarter than I about these things, so I put it back in. The guy at SeaWay thinks I might have a 30 horse leg, repainted to green. I guess nothing's impossible.<br /><br />Also, on mine, there was a small half round cork gasket, under the bottom fibre gasket, in a notch that separates the water outlet from the exhaust area. This cork gasket was not shown in any of their parts lists. I'm wondering if it was a repair for corosion, seems to be evidence of that.<br /><br />One more thing, I had to replace the bottom crank seal, the rubber was falling appart, so all this ended up being a good thing, I never would have known that seal was bad.

 

[55Crestliner]

Re: 1955 25 horse Head Gasket Bad?

Anybody? Why the stainless gasket?