Blown head gasket or???

[BCinNYC]

Recently acquired a good old Pearson Triton with an Atomic 4. Motor ran well for an hour or so, then lost compression on the two rear cylinders. I can see/feel that the valves are opening and closing.

Question is: Is this most likely a blown head gasket (that I can fix in the boat), or something more dire.

If this matters: The boat had been unused for a couple of years (out of the water) before I bought it. While the motor was running the temp and oil pressure were normal. I did discover that the choke linkage was miss-adjusted so it was running with an almost full choke - the plugs are very sooty...

First post by the way - love this site!
Barry

[Baltimore Sailor]

Most likely the head gasket. If you lose pressure on two adjacent cylinders, that is the usual culprit. I'll bet you still have the old "paper" gasket -- look at the union of the head with the block and see if there's a thin gasket or a thicker, metal-appearing gasket. The metal ones practically never blow, but those old paper ones are notorious.

[Dave Neptune]

Ouch!

Barry, welcome to the forum!
If your valves are moving all the wa a blown headgasket is most likely. I'd at least double check.
Changing out the headgasket is not to bad unless you have problems with the studs.
Ane yes indeed the A-4 does indeed use TWO headgaskets .

Good Luck and fair winds _/) _/)
Dave Neptune

[BCinNYC]

Thanks for the info. I'll check the edge of the gasket the next time I'm at the boat. I guess I was looking for a reason to feel optimistic - re-powering is not really an option now.

In any case my plan is to pull the head after haul out next month. Until then I've mounted an outboard which keeps me sailing.

Thanks Again
Barry

[CalebD]

Be an optimist.

If your A4 was running ok before this incident it is more then likely that it will run better then before if you can give it the TLC it needs.
My A4 is 43 going on 44 years old (1967 model) and our Tartan 27' is up at Nyack, NY. I am also quite fond of the looks of the older Pearsons like the Triton.
Where in the NYC area do you keep her? I'm actually in lower Manhattan.

[BCinNYC]

I keep the boat at City Island. This is my first season sailing in the Sound and I'm loving it so far. Sailed out to Greenwich CT and back last Sunday.

[Seabee Chief]

Head Gasket

Barry,

Welcome to the forum!
I had the same problem a few months ago on my newly aquired '81 Catalina C30 (30HP A4). I believe my previous owner may have overheated the engiine and fatigued the head gasket. We took her out on maybe her 5th or 6th voyage and was running the engine in light wind when I lost 50% of the power. We limped back to the dock with normal temp 140-150. We lost compression in #1 & #2 bringing us to change the head gasket. MM has a great overhaul book if you are new to the A4. Changing the head gasket is not difficult. Read the book, take your time and be patient. Also when you get it off, flush the head and the engine out good! Consider changing the thermostat as I am now changing mine after only a few months of service.
If you have any other questions, bring them up. These guys are great and should be able to help you out with anything. And if we need help there is always Don. They have helped me out considerbly.
My wife and I also love sailing the Sound, we are in Westbrook, CT.

Chief