Weird A-4 Engine Problem

[windjunkee]

Ok, so this one is very very odd and any input would be appreciated.

1970 E32-2 with an Atomic 4 engine. Raw water intake is on the starboard underside, maybe 1 ft to the outside from where the keel starts to slope down. The intake is covered by a brass strainer. When the boat was hauled in July, we took the strainer off, cleaned out the thru-hull completely and reseated the strainer.

Now the weird problem. When the boat is motoring flat or is on starboard tack, engine temperature remains constant at about 180 degrees with RPM's anywhere from 1500 to 1850. When the boat is on port tack and heel angle is plus-2 degrees, the engine temperature shoots up to 220 degrees. 5 degrees heel or more and the engine temperature closes in on 250, alarms sound and we have to back it off to idle, let it idle for a minute or more and luff the main to eliminate the heel angle, which will bring the temperature back to 180.

If we change tacks back to starboard, the temperature immediately drops.
Since the intake is on the starboard side, assumably port tack would cause the intake to be deeper in the water. The bottom is smooth so there is no turbulence being directed at the intake strainer -- at least none that we can fathom. All the intake lines are clear (i.e. no full or partial blockage). Exhaust water flow does not appear to be diminished in any way between tacks or flat water motoring.

Any thoughts?

Jim McCone
Voice of Reason E32-2 hull #134

 

[raleighm]

Atomic 4 Cooling Mystery

May I suggest that you visit www.moyermarine.com and post your problem for Don Moyer to chew on? He's the A-4 guru that I consult with any unusual problems.

Raleigh

 

[Guy Stevens]

Air instead of water

You are getting air in somewhere would be my first troubleshooting tactic. Make sure that all of the hose clamps are tight, and that there are no holes that would let air be sucked into cooling water.

It also never hurts to replace the impeller. They get hard, and worn well before they loose fins, a loss of efiency could cause something strange as well. If you are only pumping at 10% of what you should be, even a small change of an inch or two might mean the difference between cooling and not cooling.

I can't see that you are picking the thru hull out of the water on a 2 degree angle of heel.

Guy

 

[Emerald]

Another thought is do you have an interior strainer on the water intake? If so, examine where it is mounted in relation to the centerline of the boat and the waterline. It is possible you are draining it out enough to loose your continuous column of water e.g. prime for the pump when you start to heel the wrong way.


-David
Independence 31
Emerald

 

[windjunkee]

Yesterday my partner and I tried to tackle the engine overheating problem. Since my last post, we have made the following observations:

When running the A-4 at 1500-1850 rpm on flat water or on starboard tack, the engine temperature remains a pretty constant 180 degrees, according to our instrument.
When on Port Tack, as was the case returning the 55-plus miles following the Long Beach-Dana Point race, at anything greater than 2 degrees heel angle, the engine temperature jumped almost immediately to the 220 degree range. We would see quite a bit of steam coming from the exhaust, and then we would get the warning buzzer. We would turn the engine off for 30-45 seconds and the engine would cool back down below 180 degrees, in that short of a time span. Then we could run it again for at least 1/2 hour before having to shut down again.

Yesterday, we changed out the impeller, put in new hoses, tested the thermostat and acid-flushed the engine. The acid-flush got quite a bit of black, gooey looking crud (we trapped the exhaust water/acid mixture in 5 gallon buckets). We left the thermostat out for the time being, to see if maybe it is causing a steam pocket to develop while we're heeled to starboard. I'm still having trouble getting my head around the problem of why this occurs only when we're on port tack. We're going to drive-test it this week some time to see if what we did resolved the problem. I'm still nearly convinced that the engine is, plain and simple, haunted.

Jim McCone
Voice of Reason, E-32-2, Hull # 134

 

[gjersvik]

Have you ruled out a short or bad ground on the temperature sensor or gauge? Before your test-drive you way want to clean the contacts and make sure they are securely attached.

 

[hodo]

It sure sounds like you may have a wiring issue. it should take longer than 30-40 seconds to cool to 180 from 220. I tend to agree with Charlie. Try to take a halyard to a strong point on a dock and winch it in to tilt the boat. this might tell you if it relates to angle, speed, or whatever. Make sure the mooring lines are snugged and adequate before you put it in gear, if you need to. Harold

 

[Sean Engle]

You are getting air in somewhere would be my first troubleshooting tactic. Make sure that all of the hose clamps are tight, and that there are no holes that would let air be sucked into cooling water.

I can't see that you are picking the thru hull out of the water on a 2 degree angle of heel.

Guy

My vote would be for air also. Perhaps when you hauled out you lost the prime in the system - and it got sucked into the raw water side - is is stuck in there at some point where the position of the engine changes it's impact on your cooling...?

You burped the whole system (no air in either side), right? The last time I lost my prime - I put a little dish soap into the raw water pump - the resulting foam pushed out all the air (of course, seeing suds coming out your exhaust is a little freaky, but it's only for a couple of seconds...).

//sse

 

[Emerald]

We left the thermostat out for the time being, to see if maybe it is causing a steam pocket to develop

Jim McCone
Voice of Reason, E-32-2, Hull # 134

Put the thermostat back into the engine. If I remember this correctly (and I am pretty sure I do), you will never get proper cooling on the A4 if you have the thermostat out - and in fact, you'll cause overheating. If you follow the output side from the water pump, you will find that the hose goes to a T on the side of the engine, and then continues up to the thermostat housing. From the top of the thermostat housing you'll see you have another hose that is running to discharge. When the A4 thermostat is closed, water is forced through the cooling jacket via the T, when open, the water goes straight up to the thermostat housing and out, therefore you are basically doomed to overheat if the thermostat is removed, as no water will be forced through the T and into block.

The test you want to do is put the thermostat back in, and use a small clamp (can be vice-grips) preferrably with some wood "pads" (e.g two little pieces of paint stirer) to clamp off the hose between the T and the thermostat housing. This will force the water through the jacket and around the cylinders and up and through the head. The thermostat housing in the A4 is set to allow water to flow through from two directions, either up from the head after going through the engine (closed state), or pass the T to the housing cap and out.. Check and see what your temps do with this hose clamped off. If you have steam in the exhaust, you are too hot. Make sure that your intake hose from the seacock to the water pump does not rise above the water line. Do you have a waterlift muffler or a stock Ericson riser on the exhuast? There could be issues here, but let's look at the above first.

One more thought on flushing. You need to do it with the thermostat removed (so you don't destroy it with the acid), and you need to clamp the hose off between the T and the thermostat housing (to make the acid go through the block). You may need to do another flush routine, but do a sea trial first as described above.


-David
Independence 31
Emerald

 

[windjunkee]

Thanks for all the input gang. We have tried virtually everything. We tested the wires to the water flow sensor and the temperature sensor. They were all good. The port-tack overheating problem was noticed before we hauled out. In fact, while we were hauled, we pulled the raw water strainer, cleaned out the thru-hull thoroughly and rebedded the strainer. We also checked all around the intake to see if there was something on the hull that would cause a disruption in flow. Remember, the thru-hull for our engine is on the starboard side of the hull, thus, when we're on port tack, the intake is actually deeper in the water.
When we did the acid flush, we clamped off the appropriate hoses to make sure the acid mixture was forced through the engine block.
Consider that a couple of weeks ago, we spent the weekend at Catalina Island. It is a 28 mile passage. On the way over, the wind was light and, what wind there was, was coming from starboard. We ran the engine most of the way. It never overheated in 4-plus hours of motoring. On the way back, the wind was calm when we started out and we were motoring flat. No overheating. About 2 in the afternoon, light wind came up from port. As soon as we started to heel (and I'm talking about 2-3 degrees of heel angle), the temp shot up to 200 degrees, and then to 220, and then we got the alarm. And yes, if we let it sit for 30 seconds, the temp comes back down to normal operating levels and we could resume motoring for about 1/2 hour until we had to go through the process again.
If there were a wiring problem, why would it only occur on port tack? If there were air in the system, why would it only do it on port tack? I'm personally convinced that its haunted. Thats the only rational explanation.

We've yet to sea test it since this past weekend. We will be putting a new thermostat in though. There are more problems than we are willing to deal with if the engine runs cold for too long. In running the engine for about 15 minutes with the thermostat out, we barely got the temp to register on the instrument. (lowest number on the gauge is 100)

Jim McCone
Voice of Reason E-32-2 Hull #134

 

[HGSail]

I just thought I'd throw one into the wind here.

Which side is your riser mounted on, port or starboard? It is possible that if your riser is on the port side like mine. Is that as the riser is lifted in elevation you waterpump maybe having a hard time pushing the water the extra few inches up. You may want to check your pump to see if all your blades are still on the impeller. You may have lost one and may not be producing enough pressure.


Davis
E29
#224
Holy Guacamole
Davis Modlin Atomic 4

 

[windjunkee]

Thanks Davis,

That is the first rational explanation I've heard. The riser IS on the port side, and, from my time spent in the cockpit locker last saturday, relearning old contortionist moves, it does go up pretty high on the port side.
We changed the impeller. All the blades were there, but some had lost their shape and the rubber was definitely old and cracked, like it hadn't been changed in quite some time.
The old owner installed an inverter, and a huge golfcart-sized closed cell battery that all the A/C powered items can run off. However, he installed it on a fixed wooden platform that had, effectively, blocked access to the water pump. We had to make a cutout from the platform to permit access. We also changed the faceplate of the pump, with thumbscrews, so that we can easily remove the plate for access without the need for tools. Bad thing is, we always have to remove that battery ... and that sucker weighs a TON (ok, maybe not literally, but it takes two strapping, burly men to lift it from below the cockpit)
Maybe that IS the problem and the replacement of the impeller, together with the acid flush, will solve the problem. Hey, maybe it ISN'T haunted after all.

Jim McCone
Voice of Reason E-32 2 Hull #134

 

[Emerald]

Here's just a thought to mull over while you think about your water intake and exhaust systems. It really is as if you've got something working like a check valve that is somehow related to heel. This could be anything from something moving as the boat heels that then pinches a hose somewhere to a piece of debris rolling around that manages to make it's way into a critical passage when it's all right or wrong depending on your perspective

Don't rule out air. If you had a heat exchanger in this equation I'd tell you to go blead it. I really want to know where your water line is in relation to the routing of your intake for the water pump and the exhaust system and the water injection point on the exhaust, and if there are any siphon breaks or other items in the equation. You haven't omitted something like your water heater is plumbed to get hot when running the engine?

Here's something to think about as you look at your system. I've seen brake hoses on cars act as check valves where they have collapsed internally and you can put the brake on, but the caliper won't release as the fluid goes down, but doesn't come back. Obviously we're not talking brake lines here, but it is a water/hydraulic system etc. so just remember odd things like this as you look at your system.


-David
Independence 31
Emerald

 

[hodo]

Spooky A-4

The reasoning behind the thought of an electrical circuit problem was, if your wiring was not secured well or a loose connection, broken wire, etc., it could allow a change in the integrity of the system when the boat heeled only one direction. I chased a similar problem on a Valiant charging system. The owner just kept a spare regulator on board. Also check your complete exhaust system. I discovered a faulty flow check valve on my universal. The rubber seal came off the bronze flapper, and the flapper came off the pivot. When you do find the problem, let us know, cause you will be a lot more educated than we all are know. Good Luck, Fair Winds. Harold

 

[Bill Sanborn]

Wierd A-4 Cooling Prob - Was this ever rresolved?????

I ran across this old thread and now I am dying of curiosity about any resolution.

Was this a FW cooled engine??

 

[bob smith]

a-4 overheating propblem

remove 5/8 heater hose from thermostate housing to exhaust manifold inlet. install clear vinal hose and test engine for air in cooling system. If you have air bubbles. reinstall old hose and install vinal hose from tee in block to thermostate housing. test engine. keep moving backwared threw cooling system untill you find point of air entry. good luck.