Overheating, cooling or exhaust system issue?

[Chris Knudsen]

Just when I had my A4 running like a top she has blessed me with another mystery problem. Here is the rundown:

Last week I was heading out for a quick little ride. On my way out of the harbor my boat started acting strange and engine speed started fluctuating (around 1500-1700rpm.) All of a sudden I heard some "popping" sounds possibly a backfire coming from the carb and then she stopped. Since I was in the channel I immediately unfurled the genoa and sailed away. Didn't have a chance to look at anything at that time. One our way back in she started right up with no issues. The next day she began to run hot. I noticed a significant amount of steam and little water coming out. She has always steamed a tiny bit once she is warmed up but this was a lot. Almost like I was spraying for mosquitoes. The temp gauge said 240 but I don't really trust it. It didn't seem that hot, I was able to put my hand on the head while running.

Boat Specs:
1971 Ericson E32
Atomic 4 (new style, believe to be original)
Raw water cooled (fresh water lake)
No thermostat and my bypass valve was closed.
Impeller only has about 30 hours on it and it was pumping what I believe to be a normal amount (10-15 ft spurt every couple seconds) up until a week ago.
Standpipe exhaust

Here is what I have done so far and what I have observed.

1. I did a vinegar flush to make sure my passages were clean. I have a T installed between my sea cock and pump. I closed the sea cock and put a hose on the T and into a gallon of vinegar. With the engine running it sucked the first gallon down no problem. When I switched bottles all of a sudden fluid started coming out that hose. It was a nice brown mix (must be the vinegar doing its job already) and some bubbles. Actually a lot of bubbles. Do you think these are exhaust or steam? I turned off the motor and let it sit for a bit. Then I started it back up and it sucked up the second gallon of vinegar. I let it sit overnight.

2. Day two, I go back and pull the hose off the manifold (to exhaust fitting) and added a length of hose going into a bucket. Started the engine and watched the flow. It seemed to be a nice steady stream. I got about 2-2.5 gallons of water at about 1,000 rpm in a minute to a minute and a half. It is the original style pump (202?) and I don't know the flow that that it is supposed to be but I imagine that I am close to spec. The water was slightly brown by I expected that.

3. Then I take the hose that leads to the water intake on the exhaust and blew through it. Didn't feel like any restriction at all. Hooked the hose back up.

4. Ran the engine again. Very little water flow and a lot of steam. Engine is running at 220-240 (again I don't trust this number though, needle is jumping around and head wasn't crazy hot.) This time I notice a trickle of water coming off the standpipe. My standpipe is wrapped in cloth so I don't know where the water is coming from. It could be the elbow at the bottom where it is dripping from or anywhere higher up?

Where do I go from here? I am going to check the oil and also compression. Help please!!!! I just want to go sailing.

(Cross posted on Sailnet and Moyer)

 

[Afrakes]

A-4

No. 1. The water temp is way too high for a raw water cooled A-4. Have you opened the block drain that is on the front left hand side of the engine too see if you have coolant there? No. 2 remove every hose from the raw water intake to the stand pipe and make sure that they are clear. No. 3 have you ever had the left side plate off to see what may have accumulated there? Those stand pipes are pretty simple. No.4 Have you removed the hose from the lower part of the stand pipe and checked to see if it is blocked? When I redid the stand pipe on my E-27 I found that the top of the inner tube had deteriorated to the point where it would let water flow back towards the engine. Still that didn't cause a reduction in flow.

 

[Chris Knudsen]

No. 1. The water temp is way too high for a raw water cooled A-4. Have you opened the block drain that is on the front left hand side of the engine too see if you have coolant there? No. 2 remove every hose from the raw water intake to the stand pipe and make sure that they are clear. No. 3 have you ever had the left side plate off to see what may have accumulated there? Those stand pipes are pretty simple. No.4 Have you removed the hose from the lower part of the stand pipe and checked to see if it is blocked? When I redid the stand pipe on my E-27 I found that the top of the inner tube had deteriorated to the point where it would let water flow back towards the engine. Still that didn't cause a reduction in flow.

1. I have not tried that plug but that sounds like a good place to start.
2. I removed a couple of the hoses and they looked good but I plan on checking them all. I did have a steady stream out of the manifold when I pulled that one so I thought that would mean the rest must be good.
3. The left side is not accessible at all. Just to change the alternator belt is is done 100% by feel. Can't see a darn thing, not even with mirrors.
4. I took the hose going to the standpipe and was able to blow through it freely.

 

[Afrakes]

A-4

Remove the cooling water hose at the lower end of the stand pipe. Extend the hose so you can put it in a bucket. Start the engine and run briefly to see what kind of flow you have coming out of that hose. If you have good flow then the problem might be the stand pipe but I doubt it. Access to that side plate is a real bear. It gives you access to the water jacket around the cylinders. When I removed mine I ended up breaking a number of the bolts off and having to utilize the stud kit from Moyer. It is very possible that there was some debris lurking in the engine that finally got broke loose and ended up in a bad spot. If you do open the drain on the left front side of the block be prepared with a piece of wire to clear the crap that is going to be in there.

 

[Chris Knudsen]

Remove the cooling water hose at the lower end of the stand pipe. Extend the hose so you can put it in a bucket. Start the engine and run briefly to see what kind of flow you have coming out of that hose. If you have good flow then the problem might be the stand pipe but I doubt it. Access to that side plate is a real bear. It gives you access to the water jacket around the cylinders. When I removed mine I ended up breaking a number of the bolts off and having to utilize the stud kit from Moyer. It is very possible that there was some debris lurking in the engine that finally got broke loose and ended up in a bad spot. If you do open the drain on the left front side of the block be prepared with a piece of wire to clear the crap that is going to be in there.

I did take the hose off of the water outlet of the manifold and ran it into a bucket. Had about 2 gallons in a minute or so of running at 1,000 rpm.

I don't think there is any way for me to get to the side plate off without pulling the galley sink and cabinets off.

I will try that drain plug. I always thought that was oil so I never touched it. Didn't realize that it was for the water passages.