There's a hole in my motor........

[Superflid]

.....but only a small one!<br /><br />Merc 402 which runs well but seemed to have water running down from the top of it while running, at faster rpm's it was being sprayed around by the flywheel.<br /><br />Took the lid off and found a small (3 or 4mm) hole in the top of what looks like a thermostat housing. Ran the motor again and watched a small fountain spring into life!<br /><br />Two questions.<br /> Is it a thermostat housing? (My Seloc manual is none too helpful)<br /> Should there be a screw filling the hole?<br /><br />It would be easy to screw in a self-tapper with a little sealer on, just wanted the experts advice before doing the wrong thing.....

 

[KCLOST]

Re: There's a hole in my motor........

I would guess this is your poppet valve cover plate...<br /><br />I don't know what your serial# is, but take a look at this diagram, especially Part# 3, and see if this looks like the "housing" that is leaking..<br /><br /> merc.402<br /><br />It might be time for a poppet valve replacement.

 

[Superflid]

Re: There's a hole in my motor........

Thanks KCLOST.<br /><br />Serial is 9184453.<br /><br />I've taken a pic of the part, it's on Fotango.<br /><br /><br /> http://photos.fotango.com/p/eba00415342f00000005.jpg <br /><br />Might make more sense than listening to me!

 

[peterpagnott]

Re: There's a hole in my motor........

That looks like the poppet to me

 

[KCLOST]

Re: There's a hole in my motor........

Yep, that's the poppet cover... You have a faulty valve, most likely the diaphram... It's time to replace one or the other...

 

[Superflid]

Re: There's a hole in my motor........

Thanks for the help, I've just had a go at removing the bolts. The one which goes through the starter mechanism came out easily, the other one has decided to stay put!<br /><br />Tried a good dose of blowlamp and a big spanner but no luck. Left it to soak in penetrating oil overnight. Had enough of snapped bolts already.<br /><br />If I did block the hole as a temporary measure, until I got new parts, could I be damaging my motor?

 

[KCLOST]

Re: There's a hole in my motor........

Try this on that stuck bolt... If it won't budge turning it counter-clockwise (to loosen), try turning it clockwise to tighten. Now don't over do it!!!!, just give it a good gentle nudge and see if it moves a little in that direction, you may actually hear a slight pop when it breaks free.. Then go back and forth and see if it comes loose, CAREFULLY... <br /><br />That worked on a few of my cylinder head bolts..<br /><br />I'm not sure about plugging that hole, it's obviously there for a reason, I believe to release air that may hinder the ability of the poppet to open...

 

[Superflid]

Re: There's a hole in my motor........

Thanks again, I knew it must be there for a reason!<br />I'll give the bolt a try again later.

 

[jim dozier]

Re: There's a hole in my motor........

Apply heat with propane torch and alternate with liberal application of penetrting oil to the bolt. Becareful of the surrounding area. I lay fiberglass cloth over surrounding heat sensitive areas and cover with aluminum foil.