No idea what to do next

[Al Schober]

Re: first photo. WHAT are all those wires on the coil? Do you know what they are? Re: second photo. Engine isn't THAT new - it has the oil spray line to the lifters (good thing).
Original post: erratic gauges. I suspect antique wiring & bad connections.
Sudden stop: classic bad coil, but see above.
Black stuff in fuel: seems you've replaced everything but the fuel?
Why the water in the engine? Exhaust? Manifold?
Seems you have a number of issues to address. With the engine in the boat, you're forced to address them all at the same time, which is difficult. Even with a perfect rebuild from Moyer, seems the boat issues would doom the new engine in short order.

[romantic comedy]

Now is the time to use a lead down tester.

It pressurizes the cylinder and you can find where the air is escaping. May be helpful in finding where the water is entering.

[CaptainCronos]

Re: first photo. WHAT are all those wires on the coil? Do you know what they are? Re: second photo. Engine isn't THAT new - it has the oil spray line to the lifters (good thing).
Original post: erratic gauges. I suspect antique wiring & bad connections.
Sudden stop: classic bad coil, but see above.
Black stuff in fuel: seems you've replaced everything but the fuel?
Why the water in the engine? Exhaust? Manifold?
Seems you have a number of issues to address. With the engine in the boat, you're forced to address them all at the same time, which is difficult. Even with a perfect rebuild from Moyer, seems the boat issues would doom the new engine in short order.

Yes, the antique wiring and gauges were bad. All of those was replaced and even though she failed sea trials, they proved to be reliable. Yes, I do know where those wires come from going to the coil. The coil was brand new, and while it hasn't been COMPLETELY ruled out because of infant mortality, it runs the engine at this point till it can be ruled out at a later date. Fuel and its support system have been replaced. We are just down to water incursion, and stuck valve(s). Going to try pulling the head off today.

[Dave Neptune]

Captain, doing a pressure test is much easier and will give accurate results. All you need are a few plumbing pieces the shrader valve, gage and a bicycle pump.

Much easier on the knuckles too.

Dave Neptune

[CaptainCronos]

Captain, doing a pressure test is much easier and will give accurate results. All you need are a few plumbing pieces the shrader valve, gage and a bicycle pump.

Much easier on the knuckles too.

Dave Neptune

Not sure how doing a test is going to "unstick" and clean up the seats on those valves? Can you explain?

Here is the progress report so far.

Removed all the nuts, and during that process, half the studs came out. None broke off.

The thermostat is completely missing, and a ton of crap is on the inside of the cooling area that I can see so far. That's probably going to need some sort of flush. Only worked on the "front" side of the engine to start separating the head from the block and managed to pry up enough with a screwdriver to get some wooden "shim" in and out. Lots of silicone sealer around stud holes, etc.

While I don't think the PO did a rebuild, I do suspect he replaced the head gasket in the hopes of keeping the engine temps down and retarding water leaks long enough to sell the boat. I found a place that does magnaflux tests locally, so we shall see. I suspect when the head comes off, I am not going to like what I see however, I am hoping.

Some of the remaining studs look like they are wanting to let go of the head. Some do not. The long thermostat studs are one example. I might have to take a puller to those.

[zellerj]

While you are digging into your engine, it might be a good time to take off your side plate and dig all of the junk out around your cylinder walls. It is probably full of junk and crap too. But be careful and patient because these bolts are notorious for snapping off.

[CaptainCronos]

While you are digging into your engine, it might be a good time to take off your side plate and dig all of the junk out around your cylinder walls. It is probably full of junk and crap too. But be careful and patient because these bolts are notorious for snapping off.

Thanks. Yeah, I was thinking I would have to do that anyway. The water has to be getting into the #3 & 4 cylinders from somewhere. Pretty sure when they magnaflux the head, that will reveal alot too. Hoping beyond hopes that the water incursion was just a badly installed head gasket.

[sastanley]

Did you pressure test the manifold yet? I would do that, and it is easy on or off the motor.

let's hope the head yank does not reveal a mess. I had some sticky valves and repeated running and repeated MMO squirts in the plug holes eventually broke it free.

[CaptainCronos]

Ok. Manifold came off with no resistance and pressure tested via lung capacity was good. My pressure gauge came into HomeDepot and will pick that up tomorrow for more "thorough" testing. The head finally came off after I removed all the studs and it wasn't coming off till they did. Don't think they were the right lengths as 1 had like 4 washers on it under the nut. The valve cover came off but looked like the gasket wasn't aligned correctly, and the cooling cover plate looked good with the exceptions of 2 bolts which probably were the originals considering the tops were almost completely eroded away.

The cylinders held MMO for over an hour with zero leakage. The cooling area didn't look that bad all things considering. Major crud in the valves though with severe dirt/gumminess around the 4'th cylinder. Both valves looked just nasty.

The exhaust hose and exhaust pipe produced no back pressure to a shop vac in either suck or blow mode so that appears to be clear. The oil was still milky from the last time, so I drained that.

My cooling didn't have a bypass valve or hosing system. A straight hose from the RWC pump. In fact, that port was plugged off at the thermostat housing. It appears to have been running without a thermostat for quite a while even. Suspect that just made the engine run cooler for longer? Open to ideas on that one. Never saw the engine above 140F. Guess next step would be to lap the valves and adjust the tappets. First time for me doing that. Covered up the holes below the tappets. Guess MMI is going to get an order tomorrow for some stuff.

[sastanley]

When preparing for head re-installation, make sure you get the "fat" nuts on MMI's site..those are designed to secure the head via the studs without washers. I have washers and little nuts all over mine from PO's work. :thumbsdown:

except i can't find them over in the catalog ??
edit here they are..in the block section.. https://moyermarine.com/product/head...d-oblk_08_188/

[CaptainCronos]

When preparing for head re-installation, make sure you get the "fat" nuts on MMI's site..those are designed to secure the head via the studs without washers. I have washers and little nuts all over mine from PO's work. :thumbsdown:

except i can't find them over in the catalog ??
edit here they are..in the block section.. https://moyermarine.com/product/head...d-oblk_08_188/

17 of those hugh? Does save me having to use washers, I guess that's a good thing. Spent the day scraping bits of gaskets off the exhaust manifold, and the water jacket plate, and the valve cover. Seems the valve cover plate was cork? Confused as to why someone would permatex that down (incorrectly no less) when someone has to go in there like every 100 hours.

Picked up the 15 psi gauge with shrader valve. Adapted that for 1/2 hosing to pressure test the water jacket. Started adding gaskets, studs, etc to shopping cart and figured out that I have gone past $250 and have no guarantee that the block isn't cracked or something and no way of knowing until it's all back together.

[CaptainCronos]

Ok. Parts are on order.

[sastanley]

CaptCro,
I always recommend chatting directly with Ken when you are ordering parts (call the parts line and have a talk with him about everything you are dealing with.) He has built more A-4s in his day than you know. He always provides excellent guidance.

[CaptainCronos]

Thanks. Yeah. We had a nice long discussion.