Request advice with stalling engine

[Jon K]

Thanks in advance for your advice.

My 1985 Atomic 4 has developed some problems, it stalls after reaching 180 degrees and won't restart until it cools. It also has a history of performing fine under power, then stalling when brought to idle when returning to port.

History:

I bought a late 1970s Ranger 28 in 2006, the marine surveyor said it was sound and we began sailing the boat and updating the cabin.

Recently I have noticed that the wiring in this negative-ground system uses different colors of wire, spliced partway through each run to another color. With red, orange, white and yellow wires, the only color absent on the ground side is black. I've added a second cigarette lighter receptacle so the GPS and handheld spotlight can be run at the same time, not much else.

I read about the Atomic 4 and learned how to do a few things, including how to change the oil. It is a traditional, un-upgraded engine with a new heat exchanger - freshwater cooling and two pumps. It burns a little oil, perhaps a quarter-litre per season of 10-12 hours of use. I tend to run the engine near or at top RPM, using my ear to avoid over-throttling. After 5 seasons I have put about 70 hours on the engine.

At one point the engine was overheating, it turns out that the saltwater through-hull was clogged with seaweed. A coathanger was an easy tool to clear the clog. Now it runs at 180 degrees all the time.

Every season we make a long trip that begins with a 5-hour crossing of the Georgia Straight between the mainland and the Gulf Islands, here in the Vancouver, BC area.

In the fourth year, returning from one such trip, the engine stalled after a few hours, when brought to idle from 2-3 hours at full speed. We had slowed to make a passage between two islands, possible only at flat water. Luckily a passing motorboat offered us a tow through, and we decided to make port nearby to diagnose the problem. As it turned out, during the passage the problem had cleared and we were able to restart and continue home.

After a speedy 3.5 hour crossing under sail and 2/3 power, I idled the engine to drop sails and moor the boat. Engine died and would not restart. We took a tow in and ended the season.

Last year in Spring I took the boat for service, only to stall half-way after running for about an hour. A friend brought some methyl hydrate which we added to the fuel, and we blew through the line to attempt to clear any blockage - the ragged running of the engine suggested a fuel starvation problem.

After 30 minutes or so the engine restarted, and so I handed the boat over the boat yard manager who convinced me to install new fuel lines, a Rakor filter, and an electric fuel pump to pull the gas through it. Electronic ignition was added, as well as new plugs and wires.

After the service the engine seemed to run well, however issues soon developed:

1. The electric fuel pump wasn't working -- I rewired it myself by adding a new hot lead from the engine cutoff switch. Now it spurts gas at the carb whenever I test it.

2. The common ground for some house wiring is gone; I rewired the house water pump with a ground directly to the gear housing. The mast light stays on whenever the batteries are engaged.

I think the mechanic was a little clumsy, or changed the wiring while installing the fuel pump. These are not critical issues for me, I will rewire at some future time. Just more data points.

This season I have completed a recent journey with the following symptoms:

3. Fairly constant loss of coolant, needing 1/2 litre for 30 minutes engine time. First noted when engine overheated with steam in the exhaust. I thought at first it was oil burning, but the cloud was white and smelled like antifreeze not stinky like oil.

4. During the same hot-engine breakdown I pulled plugs 1 and 2. Both looked okay, but I saw no fuel in the cylinders while cranking. Maybe it just evaporates in the hot engine. No obvious issues in the cylinder or plugs.

5. At the same time I tested for spark -- good spark. Tested for fuel at the carb -- lots of gas.

The engine restarted after ccooling, but once again stalled and would not restart when we slowed down to begin mooring.

So I tested a few things:

6. Thermostat works fine in boiling water.

7. Oil at Low mark, I topped it up, lubricant was a little dark but no obvious water.

8. Engine always starts easily and runs fine at idle, or while cool.

It's dificult to access the carb, although the fuel pump and filters are available. The other side of the engine is somewhat accessible, and the head area is exposed under the companionway stairs.

I am tempted to remove the head but I'm experienced mechanically just enough to know that this may introduce more issues, and right now the engine runs, enough at least for local sailing.

I hope the forum can offer me suggestions to diagnose the problem. I am motivated, have tools, shore power, flashlights, and a multimeter. I can rent or borrow a compression tester and know what it is for.

Where do I go from here?

- Jon

[Dave Neptune]

Jon, first thing welcome to the Afourian Forum!
Lots os stuff listed to dig through. Did you check for spark when the engine stalled? Your ignition upgrade may not include the properly rated coil and it is "opening" once it gets hot and then "closes" after cooling to fire up again. There has been much todo regarding this on the forum.
As far as the coolant leaking do you see any in the bilge or leaking anywhere on the engine? If not and you are using that much coolant it's probably time to check the intake/exhaust manifolds integrity. Not to bad of a job.
Don't R&R the head unless it is needed and it is not YET! A simple compression check will let us know if you are loosing coolant throuugh the heads gasket. Have you done a compression check?
Remember to close the water intake while cranking in hard starting diagnosis so you don't fill the exhaust risking water encroachment from the exhaust side to the engine .

Dave Neptune

[Bold Rascal]

Your going to receive some very good advice from this forum.
If you already have a manual that's the first place I would start. Excellent trouble shooting guidelines are there. If you don't have one, get one....

180deg F is pretty close to normal temp for the A4.
The symptom of the engine failing and needing to cool before it will restart is most likely electrical. There have been many recent threads discussing this symptom.

The loss of coolant out the exhaust should be concerning. Hopefully it's just a failed gasket. Have you performed a thumb compression test on all cylinders? Do get yourself a compression tester and document your compression on each cyclinder. Your looking for consistent readings from all cylinders.

It's a Good idea to keep checking that oil for water contamination.

Do you need to choke your engine at all when starting it cold? If not or very little you might be running a tad rich on your fuel mixture.

If your satisfied that the engine runs well enough for local sailing it's your call to delay seeking out and correcting the problem(s). If you choose to sail be safe and extra deligent to monitor your engine and fluids at regular intervals. Like before, during and after each sail.

Again. welcome to the Forum.

Mike

[ndutton]

Compliments on a detailed description of symptoms, so detailed in fact that what's not there may be informative too. I think there might be a combination of problems.

Coolant loss
The first thing I'd do is pressure test the manifold. This can be done with the manifold on the engine and is pretty straightforward. The test will eliminate or confirm the manifold as the cause of the coolant loss and point you in a direction for repair.

Original stalling problem
It sounds like it may have been fuel related as you and the mechanic suspected. The addition of a fuel filter and hose replacement probably resolved any fuel contamination problems from then on but here's one of those things you didn't say. I didn't see where the carburetor was cleaned and rebuilt. If you've owned the boat for 6 years, had possible contamination problems and haven't rebuilt the carburetor, it's overdue. It should have been done when the filter was added for a complete repair. Even if the carburetor is clean, where's the harm?

Electronic ignition upgrade
We're all thinking the same thing. Let me ask this specific question though: you correlate the current stalling problem to engine temperature but can you instead tell us the time line in a stalling episode? What we're looking for is somewhere around 45 minutes run time before the engine slows and dies much like fuel starvation. Following a 20 minute or so cooling off period she'll start only to stall again after a little less run time.

Here's my guess of what's gone on:

• 24 year old installation with a deteriorating fuel system. Possible hose decomposition due to ethanol in non-ethanol rated hoses and possible tank contamination. Issue resolved with hose replacement and filter addition.
• Electronic ignition upgrade performed at the same time as the fuel system repairs which brought on another problem with similar symptoms as the previously resolved fuel issue. You traded one problem for another. I did not read the coil was replaced in the EI upgrade. This is critical with electronic ignition.
• I don't think the coolant loss is contributing to the stalling problems.

[Jon K]

Okay, Neil Mike and Dave, thanks for the quick response and your suggestions!

I will check the coil type and model, I assume it is new.

As for coolant, there is no obvious leak or coolant in the bilge, but I will put down a clean rag to see what it picks up.

The mainfold integrity tests -- does that mean I should remove the hoses and try to pressure test the exhaust manifold from outside the engine? I'll have to do some research on the forum to find out the best way to do that test.

As for how much choke when starting, I always use full choke when cold but it isn't needed when the engine is warm, however I have never tuned the carburetor. I will need to understand the carb and clean it at some point. So it may well be running rich right now, not sure.

Compression test, either with my thumb or a tester, that I will do asap as well.

To Neil's question of the timeline before stalling, 45 minutes is an average, never less than that anyway. If it is specific to how hot the engine gets, longer times before a stalling episode may occur during lower engine load/rpms I suppose.

I did make a 3.5 hour crossing only to stall on arrival when going to idle. That has happened three times at least after the cooled engine was restarted during a journey including last week.

And Mike, the reason I considered pulling the head was due a suggestion that there might be a blown head gasket. That is unconfirmed and would take me out of commission entirely until completed -- but I am committed to diagnosing and solving these issues with a still-running motor. I would rather sail/cruise but first priority is a reliable engine!

Also, I never knew about water encroachment via the exhaust, I will close that port next time I'm cranking for more than a few cycles. Will try to remember to open it after as well!

Thanks again for pointing me in the right direction, I'll return with more information.

- Jon

[roadnsky]

Jon-
Here are a couple of threads to read thru regarding your manifold testing...

http://www.moyermarine.com/forums/sh...+pressure+test

http://www.moyermarine.com/forums/sh...+pressure+test

[Jon K]

I did a compression test with the following results.

All plugs were somewhat black with carbon.

Cold compression test

#1 - 90
#2 - 95
#3 - 100
#4 - 95

Oil pressure at high rpm: 34 psi

Engine started cold with no choke.

I ran the engine with saltwater cock closed, it soon overheated to 212/220 with lots of steam in the exhaust (photo below). In that process it ran hot (180 to 200) for 10 minutes without failure. Dropping to idle while the temp gauge read 220, it did not stall.

The electronic ignition seems to be the new item attached below the distributor (photo below). The new coil seems to be a tall black can 3 inches in diameter by 6 inches tall with the main distributor wire coming out of it. Both are new; no brand or model number visible.

I have attached today's photos of the steamy exhaust and oil pressure and temperature gauge during today's hot run, and a photo of the new ignition components.

Questions:

Still unclear about the steam in the exhaust -- what are the possibilities.

Does the compression test rule out head gasket failure or other issues.

If the ignition system (coil, electronic ignition and wires) came from Moyer last year, when the boat was in the shop, does the picture agree. If so, or if not, how to test coil failure etc.

Last year the mechanic ordered ignition parts from the East Coast, likely to have been Moyer Marine.

Neil's description of the failure scenario (45 minutes run time) seems very close to my symptoms. They seem to have persisted through a fuel system upgrade and electronic ignition upgrade. What does this indicate?

Thanks for the input,

- Jon

[Jon K]

Thanks to all of you for following up on this thread.

I finally got some time to continue gathering information, including what a Schraeder valve is, and why not to buy a bicycle pump at Walmart.

Here is what I know:

1. Engine loses coolant during regular use.

2. Engine stalls after 45 minutes to an hour of full speed, will not restart until it cools again.

3. Exhaust manifold cooling jacket holds 20 pounds of air pressure for 20 minutes.

4. Block cooling circuit from Obendorfer freshwater pump output hose to thermostat output coupling, with no thermostat, holds 22 pounds of air pressure for 20 minutes.

5. With the heat exchanger cap off, there are visible bubbles in the freshwater coolant, frothing when the engine revs to 2000 - 3000 rpm.

6. Freshwater pump looks good -- newish impeller and I sealed the gasket and tightened the screws.

7. Thermostat housing looks good -- cleaned and sealed the gasket, tightened the nuts.

8. Oil looks good -- no froth or other indication on the dipstick.

9. Cold compression test looks good -- no liquid, 90 - 105 compression.

10. Coolant hoses look good, and circuits test with good pressure.

11. Plugs are carboned, but mixture is rich.

So where is the steam coming from, and why does it lose coolant? At the beginning of this testing cycle there was no water or coolant in the bilge. Now of course there's lots because of changing the hoses and so on.

Where do I go from here? I could pressure test the heat exchanger, take her on a test run, or do the head gasket.

Is the head gasket a lot of work? I have access to the engine top and a few tools. The head bolts or nuts are rusty but I think they would come off.

If so, do I have the head machined or just add silicone to the gasket, or put new gaskets?

If I pressure test the heat exchanger freshwater circuit I might find air coming in. I could also replace all the hoses, although they and the heat exchanger look very new and clean.

I did hope that Neil was right about the exhaust cooling sleeve, but it holds tons of air. I got a tire valve stem, put it in a hose and clamp, and clamped it on. The other end I got a garden hose nipple, clamped it into a coolant hose, and added a garden hose close cap off my sprinkler to close it up. It took two tries tightening up until it held air, but the block cooling circuit and the exhaust manifold cooling circuit are tested without leaks. So I think it's not a cracked block, at least when cold.

Thanks in advance for your advice,

- Jon K.

[ndutton]

Your pressure testing indicates a sound block and manifold. I wouldn't touch the head gasket given these tests and your reported compression. The heat exchanger is next, cap on. It and the Oberdorfer FW pump are really the only components left.

Sounds like the coil is shot too.

Great testing and report. It's nice to have solid information.

[Mo]

My thoughts as well Neil and that sounds like it if there is no engine performance problems.

[Jon K]

So if I close the saltwater cock to heat up the engine, where does the steam come from?

1. Pressure test of FW side of heat exchanger failed. It won't hold 5 pounds of air pressure.

2. Going to sail today, visiting friends cabin on Gambier Island. Change hoses to send raw water pump output to freshwater pump inlet, through engine to exhaust manifold cooling jacket, change hose to send manifold outlet to exhaust. Two pumps, lots of cooling. Engine at or below 100 degrees.

Voila, raw water cooling. Left the thermostat out so temp never got beyond 100 degrees. Checked that water temperature gauge sending unit was still in the system, it is beside the thermometer housing and reads correctly.

3. Ran under power for 1 hour, stopped then ran again for another 1 hour. Dropped to idle to lower mainsail, engine stalled. (Stall on idle is ongoing problem). Engine temp read 140 degrees. Possibly less cooling during idle, engine still hot?

4. Waited a few minutes, engine restarted and ran fine for another 20 minutes, had dinner. Came home 1.5 hours, engine temp 100 degrees, no issues.

Stall on idle problem happened at 2 hours, engine temp 140. When engine was cool, did not fail as before. I think this points to a temperature related problem.

Neil, the cold coil resistance is 3.1 ohms. I just read the coil thread, will try to think about that. Measure when hot?

Great to be on the water today/tonight, full moon guided us home. Trying not to think about the saltwater cooling the engine.

Answer: Steam caused by freshwater and antifreeze pushing into the saltwater circuit at the exchanger and out the exhaust. Seems a likely scenario.

- Jon K.

[ndutton]

You have it surrounded Jon. Install a new heat exchanger and the cooling system issue is resolved. Nice work with the pressure testing. It took you directly to the problem without guesswork.

Your coil seems to be Okay although I'd still like to see one of slightly greater resistance for longevity (suggested on principle only). Given your history of shut downs I'd change it anyway.

As for the occasional stalling at idle, at what RPM do you customarily idle in gear? This could be as simple as a minor adjustment. Dare I ask, do you have a PCV valve installed?