Low power, Exhaust and raw water leaking from starter side

[mtbksouth]

Hey friends. Love these forums, have been using yall's wisdom a ton (but clearly not enough) for the past couple years since acquiring my first boat. I am not a motorhead and am still figuring out the basics. First time posting - I apologize in advance for the onslaught of information and questions.

Took my Pearson 30 with a late-model A4 out for the first time this season and was getting a lot of exhaust in the cabin, a rapid but steady clicking/ticking sound from the engine, and low power - topping out at about 4.5 knots (normally I get just over 6).

After a lot of googling and reading the forum I concluded I had a stuck valve. I took the spark plugs out, poured some MMO in each hole, hand-cranked the engine a few turns, then let it sit for a beer or two. I started it again, but still had ticking and exhaust. I took a video at this point, which I'll link in a moment.

I repeated the procedure the next day, but let the MMO sit for much longer. I noticed that when hand cranking, I could see the valves going up and down in each hole, and if I rested an allen wrench on the top of the valve, could feel them going up and down - I did this for all four of them. I concluded then that they are not, in fact, stuck; or at least, that they are no longer stuck.

The videos I took are here: https://photos.app.goo.gl/P2RANTV1fNk6mR6V9 (showing mostly water leak) and here: https://photos.app.goo.gl/7kRXA6KYoMhySnLe6 (showing mostly exhaust leak) . Both exhaust, and raw water, seem to be leaking out of the starter side of the engine, behind a plate/covering of some kind. I also noticed:
- my temperature doesn't climb above 120, and that it sort of stuck at 120 for hours after I stopped my test. Broken thermostat?
- what felt like oil on the tube leading to the thermostat. Maybe just soot and water though? Why would oil be getting into the thermostat?
- oil in the exhaust - even after 5-10 minutes of idling. Is that possibly residue from the MMO I put in the spark plug holes? Or is there likely a leak in the oil system somewhere?
- Finally, I noticed that some, but less, bluish fumes are emitted from the oil filler cap thing.

My questions:
- I plan to replace the thermostat and do a compression test; is that a good next step? Any other recommendations?
- any idea what the ticking noise is? Is it just the sound of exhaust squeezing out from behind that plate?
- are a few fumes emitting from the oil filler cap area normal? Or is that a symptom of a bigger issue?
- Could the drop in power be from a stuck valve that I happened to fix, or is it likely from something else?
- if oil is leaking into the water/exhaust symptom, am I boned?
- what is that plate on the side of the engine called that's leaking water? Do I need to replace it or a gasket underneath?

Thanks all,
Mike

[Ando]

Hi Mike,
I can say for certain that the plate from which the water is leaking is called a water jacket plate. Mmi has a kit that replaces the bolts that are holding your Water jacket plate in place, to studs with nuts for a tighter fit. You will need a new gasket for that water jacket plate as well. When you do remove the plate, if there is any corrosion in the holes where the studs go, mmi has a repair kit for that too.

The ticking sound seems to me like the sound of the blow-by (The exhaust fumes) seeping out from what seems to be the head but I can’t say for certain from the video.

[Ando]

I also have blow-by coming out the oil fill port

[Ando]

As for your other questions, I'm sure more help will be on the way from the more learned

[Surcouf]

So just based on the description, I was about to recommend to check if you do not have a blockage of the exhaust (blocked manifold, crumbled exhaust flex hose etc...), as this would explain low power, and several of the other items described

The water jacket plate leak is a very classic. Mine failed (a small hole in the middle of the plate, that became a huge one when I removed it and scatched the surface with my nail, metal was gone), and I was able to change it quickly thanks to MM, without having to install the studs kit.

But the videos are telling a very different story.... an exhaust leak on that side of the engine screams head gasket. any mayonnaise in your oil?
I strongly recommend to wait for some more experienced Afourians opinion, but I would not run this engine anymore, just for the risk of exhaust gases intoxication, and to make sure to avoid mixing oil and water and filling your oil system with a sticking goo. That would change your situation from sh”””tty to catastrophic.

Sorry mate, worst time of the year to have to pull the head. I went through that this winter, and finally started my engine late last night. If you have to pull the head just to change the gasket, it is not a minor job for sure, but feasible with the engine in your boat, but not in the engine bay. Ken will be able to help you for parts and the rest of the forum for the step by step operation (MM manual an absolute requirement)

Edit: I went back to videos once more: I am 90% sure it is a head gasket: it is possible to see exhaust gases leak “Pulsing” with each engine cycle, very distinctive “pshit pshit” noise. Takes me right back to last Labor Day when I had a similar leak on a destroyed spark plug. I would bet on a head gasket (Another version of the worst case would be a hole in the head itself. Would require you to buy another head. If you get there, PM me, another Afourian kindly proposed me his spare last Fall, but mine ended up being fine)

[Dave Neptune]

Mike, welcome to the MMI Afourian Forum.

Looked at the video and it is definitely a blown head gasket. Not to uncommon under the t-stat housing. The water just may be coming out of the head too as it looks to be "running down" on the cover plate.

I'd pull the head first then check the plate. A head gasket replacement is rather simple on one of these "flatheads" as it is just basically a plate.

Dave Neptune

[mtbksouth]

Ando, thanks for your responses. I'll certainly order a new water jacket gasket and quite possibly a stud conversion kit as well. I assume the bit of blow-by from the oil fill port isn't a major concern.

Surcouf, partially blocked exhaust is possible, but it's certainly not entirely blocked, as I'm still seeing exhaust and water coming steadily out the back. It would probably be inside the manifold if so; the flex hoses look fine if I recall correctly. I didn't see anything other than somewhat darkened oil when I check the dipstick; if I were looking for mayo, would it show up there, or would I need to take a sample from elsewhere?

Dave, appreciate the confirmation. Guess it's time to pull the head. I have the moyer bible, will start reading. Surcouf, Are you sure I can't do so with the engine remaining in place? In spite of the awkward video, I have pretty decent access from the manifold side and front once I remove a bit of wood.

Thanks again gents, wish me luck.

[Surcouf]

Surcouf, partially blocked exhaust is possible, but it's certainly not entirely blocked, as I'm still seeing exhaust and water coming steadily out the back. It would probably be inside the manifold if so; the flex hoses look fine if I recall correctly. I didn't see anything other than somewhat darkened oil when I check the dipstick; if I were looking for mayo, would it show up there, or would I need to take a sample from elsewhere? No, the dipstick is good enough.

Surcouf, Are you sure I can't do so with the engine remaining in place? In spite of the awkward video, I have pretty decent access from the manifold side and front once I remove a bit of wood. no absolutely not sure. If your access is decent, it may absolutely be possible. I have never been in a Pearson 30.

Thanks again gents, wish me luck.

Now that you are going for it, first thing you have to do is decide on your scope. The concern is always the risk to do something that is not 100% required now, but a very good preventive maintenance thing to do... I would be thinking of:
- water jacket plate: great time to remove it, check that it is not about to die, and clean thoroughly behind it. You could remove the plate now and assess if you only need a gasket. Risk: if it does not leak now, you may get into leaky screws, requiring new stud kits etc
- manifold: it is in theory possible to remove the head without removing the manifold. But will make head removal much harder. Let see what the others recommend. So a gasket here and new studs
- if the manifold goes, you want to remove the valve cover and adjust them, as everything is gone for access. So a gasket here.
- miscellaneous things you need: a set of taps to clean all threads, take notes of every bolt / nut / screw that comes out, and buy everything new. I broke several of the old ones trying to re-use them, and it is a pain in th b... . Not sure if it should be stainless / grade 5 or 8 ... Everything that MM offers, I would recommend to buy from them. And Permatex!
- you may want to consider some painting to prevent rust. But the is the open door to a lot larger scope. Do not ask how I know that..

[roadnsky]

Mike-
First, WELCOME to the crew!
I'd give Dave's advice a lot of credence. (He's got a lot of miles under his keel)

I also agree that with decent engine access, you can do the head job "in situ"

I would strongly advise you to give Ken a call (610.421.4436)...
Just chatting with him will be worth it.
He will be able to ask you questions and give you tidbits of advice that just can't be replicated here in our forum.
And you'll be certain to come away with exactly the parts you need.

[Dave Neptune]

Mike, if you are going to do in situ I would suggest removing the manifold. You can disconnect the carb and manifold without much knuckle busting. Removing them will give far better access to scraping and cleaning the block surface.

Now is not the time to go "cheap"! If you are suspect about the head-studs in the least replace them. It is also a lot easier to clean the block surface without the studs in place. Seal them with P-tex #2 or Aviation grade.

Re the "blow-by", I would not worry about it much unless you want to pull the beastie and rebuild. If the engine was running good before the gasket let go, replacing it will get you back to there for sure. And often blow-by is just to much advance in the timing~~we can deal with later as it is not a biggie.

You can decide on the one or two gaskets. I prefer just one for strength and integrity of the sealing. Stacked gaskets just aren't as strong, but in these old low compression beasties it just is NOTY a big deal.

Dave Neptune

[ronstory]

You can decide on the one or two gaskets. I prefer just one for strength and integrity of the sealing. Stacked gaskets just aren't as strong, but in these old low compression beasties it just is NOTY a big deal.

Dave Neptune

Just curious... NOTY = ?

[Dave Neptune]

Ron, it equals "NOT" with an extra "Y" as a typo I failed to catch.

Did that influence my grade ?

Dave Neptune

[ronstory]

... no, you still get a gold star.

[mtbksouth]

Thanks again for your advice - just a quick update. I called Ken (on Jerry's advice, thanks Jerry) and he was fairly certain it was a compromised head. I got the alternator, coil, carb, manifold, and water hoses off, and after some convincing, the thermostat, and sure enough, underneath the thermostat, daylight shone through a hole in the floor of the head. As I attempted to remove the head itself, I widened that hole considerably when attempting to wedge a flathead screwdriver under that side of the head, and instead peircing through the rusted metal. Ken was spot on.

So, although I'm sure I also have a worn head gasket, it seems I'll also be needing a new head. I'll post an update if anything else interesting develops. Thanks again.

Video of the hole: https://photos.app.goo.gl/ksVJDuoEEHCdqZE16

[roadnsky]

Credit where it's due...

Looked at the video and it is definitely a blown head gasket. Not to uncommon under the t-stat housing.

Thanks for the Thanks.

Note that Dave called it back in his post #6.
But I'm sure having Ken back up that advice and get you the right parts is the cherry on top.