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Old 07-29-2020, 01:19 AM
outoftheblue outoftheblue is offline
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Maybe the gears?

Hi everyone, this is my first request for help here!

I have a 1967 CAL 36 sailboat with an A4.

Engine runs great....in idle even at high RPM (2000) forever.

I've been having a unique issue for the last few years.

When I engage the transmission and raise the RPM to about 1500, it runs great with good power but in about a minute (every time) the RPM starts slowly dropping and if I let it, it will stall.
I can pull the throttle to keep it going until the end of the range of the cable and it will stall...but slowly, gradually.

What i have done so far:
Replaced the carburetor, installed electric fuel pump, new fuel filter and water separator,thermostat, checked fuel hose, tank vent, compression check,
plugs, points....checked the exhaust for restriction and more.
None of the above changes made any difference, it has been stalling the same way, again, slowly, gradually in gear at higher RPM.

From the beginning I had a feeling it might be the trans or the V drive but don't know how to test that?
The shaft was pulled out and the stuffing box and bushings rebuilt but that mad no difference either?

I had mechanics check it out but eventually they leave without having an idea of how to solve this mystery!

I am very curious what I have missed or how I can move forward?
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Old 07-29-2020, 10:09 AM
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Welcome to the crew! You're in the right place.

Do you know the condition of your exhaust? Last time it was rebuilt?

Also, let's try a simple test...
Try running with the fuel fill cap OFF to see if you get the same results.
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Old 07-29-2020, 10:58 AM
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do you have a pressure gage on the fuel supply just before the carburetor? That would allow to rule out all fuel tank / fuel pump / fuel filters / air ingress issues.

When the engine rpm slows down, have you tried to spray start-pilot on the carb? If the rpm does not change much and keeps going down, it would suggest that fuel supply if adequate, and that engine is not starving fuel.

I recommend also to verify what Jerry mentioned before, regarding exhaust pressure: do you have a exhaust lift? direct exhaust like a Catalina 27? Ever checked if there was no exhaust flex hose pipe crumbling on itself? pluggage in the exhasut? The fact that you run a minute stable tend to show that your manifold is likely not plugged, as it would not even run one minute. But could be a poorly working water lift due to flow restrictions?

anyway, you will find on that forum a few individuals that love these kinds of hard to find issues, especially as you seem to have already been checking quite a few things...
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Old 07-29-2020, 11:07 AM
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If it is in the trans as you suspect the resistance necessary to stall would create a good deal of heat. Is the trans area much hotter than the engine block? This is a very doubtful cause of stalling.

When it stalls does it just slowly come to a stop or does it shake a shudder a bit when stopping?

I suspect it is fuel related and a pressure gage would answer that if just a few minutes.

Did you do any checks once stalled like spark?

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Old 07-29-2020, 11:10 AM
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Oops

Oops I forgot to welcome you to the MMI Afourian Forum.

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Old 07-29-2020, 11:24 AM
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IT COULD BE, IT COULD , IT COULD BE..........

Once the engine starts pull wire off spark plug. If the engine runs better on three cylinders it could be a exhaust system problem.

Rig up a auxiliary fuel tank directly to the fuel pump, bypassing the boats part of the fuel system. It could be a blockage in the pickup tube in the fuel tank or a blocked filter. Run the electric fuel pump straight from the battery. It could be something in the wiring circuit to the fuel pump.
Does choking the engine the engine help? It could be something weird in the carburetor.

Report back with the result of these tests. We'll tell you what to do next.

Others will have other approaches and ideas. Consider them also.

As noted a fuel pressure gauge would be a useful diagnostic tool.

ex TRUE GRIT
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Old 07-29-2020, 11:37 AM
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Quote:
Originally Posted by outoftheblue View Post
Hi everyone, this is my first request for help here!
I had mechanics check it out but eventually they leave without having an idea of how to solve this mystery!
?
DITCH THE MECHANIC!!!! "Mechanics" are for the most part are a waste of time and money for an A4.
You have several tests mentioned so far in this thread. Report back with the results. Your engine will run correctly. No ifs, ands, or buts.

ex TRUE GRIT
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Old 07-29-2020, 03:48 PM
JOHN COOKSON JOHN COOKSON is offline
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Quote:
Originally Posted by Dave Neptune View Post
If it is in the trans as you suspect the resistance necessary to stall would create a good deal of heat. Is the trans area much hotter than the engine block? This is a very doubtful cause of stalling.
Dave Neptune
Is the prop fouled?
The prop can be fouled and whatever is fouling it sort of stays a ball around the prop at low RPMs and is flung out by centrifugal force at higher RPMs causing the engine to stall. (Don't ask how I know this.)
Maybe the reason neither you or the "mechanic" could not find the engine problem because there is no engine problem?

ex TRUE GRIT
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Old 07-30-2020, 09:41 PM
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Well, you have an impressive list of work done with replacements etc. I also vote for the installation of a liquid filled 0-15ps1 fuel pressure gauge and fitting between the carb and fuel pump [total about $35]. So far you have received a lot good logical advise and I would like to hear the results of running off an auxiliary tank. With a 1967 Cal 36 you have an early model A4 with the small Prestolite distributor [condenser screwed on outside]. If you would like to humor me pull the points plate from the distributor and check the springs and advance weights for proper function, even change springs [moyer] if they are original. Also, the little screw that holds/grounds the condenser may not be original and if the threads are a little too long they penetrate the housing wall and mess up the mechanism.

I have a friend with a restored 31 Chevy with a simple distributor with a manual cabal advance. The cable slipped and wasn't advancing the timing. The engine ran fine in neutral but bogged down under load [going up small hill etc]
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Old 07-31-2020, 07:38 PM
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Quote:
Originally Posted by roadnsky View Post
Welcome to the crew! You're in the right place.

Do you know the condition of your exhaust? Last time it was rebuilt?

Also, let's try a simple test...
Try running with the fuel fill cap OFF to see if you get the same results.
Hi, thank you for responding. Glad to be here!
I actually removed the whole exhaust system and tested it. it was clean.
i also had the engine run with the cap off.
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Old 07-31-2020, 07:41 PM
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Quote:
Originally Posted by Surcouf View Post
do you have a pressure gage on the fuel supply just before the carburetor? That would allow to rule out all fuel tank / fuel pump / fuel filters / air ingress issues.

When the engine rpm slows down, have you tried to spray start-pilot on the carb? If the rpm does not change much and keeps going down, it would suggest that fuel supply if adequate, and that engine is not starving fuel.

I recommend also to verify what Jerry mentioned before, regarding exhaust pressure: do you have a exhaust lift? direct exhaust like a Catalina 27? Ever checked if there was no exhaust flex hose pipe crumbling on itself? pluggage in the exhasut? The fact that you run a minute stable tend to show that your manifold is likely not plugged, as it would not even run one minute. But could be a poorly working water lift due to flow restrictions?

anyway, you will find on that forum a few individuals that love these kinds of hard to find issues, especially as you seem to have already been checking quite a few things...
Thank you,

I have checked the exhaust and it has a great water flow out the exhaust pipe.
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Old 07-31-2020, 08:03 PM
outoftheblue outoftheblue is offline
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Quote:
Originally Posted by JOHN COOKSON View Post
Once the engine starts pull wire off spark plug. If the engine runs better on three cylinders it could be a exhaust system problem.

Rig up a auxiliary fuel tank directly to the fuel pump, bypassing the boats part of the fuel system. It could be a blockage in the pickup tube in the fuel tank or a blocked filter. Run the electric fuel pump straight from the battery. It could be something in the wiring circuit to the fuel pump.
Does choking the engine the engine help? It could be something weird in the carburetor.

Report back with the result of these tests. We'll tell you what to do next.

Others will have other approaches and ideas. Consider them also.

As noted a fuel pressure gauge would be a useful diagnostic tool.

ex TRUE GRIT
Thank you!
I have ran the engine from a spare tank, connected to the electric fuel pump, no difference but I will repeat because vaguely i rememeber that it ran longer before slowly running out of power but eventually it slowly stalled.
i will repeat the spark plug test but it ran worse on three as far as I remember? I will repeat that.
Chocking, I will ave to try that.
I will test fuel pressure when i get a gauge for that.
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Old 07-31-2020, 08:06 PM
outoftheblue outoftheblue is offline
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Quote:
Originally Posted by JOHN COOKSON View Post
Is the prop fouled?
The prop can be fouled and whatever is fouling it sort of stays a ball around the prop at low RPMs and is flung out by centrifugal force at higher RPMs causing the engine to stall. (Don't ask how I know this.)
Maybe the reason neither you or the "mechanic" could not find the engine problem because there is no engine problem?

ex TRUE GRIT
Interesting idea!
I have a two blade folding prop but it is clean.
This stalling issue has been a problem for a long time and boat gets cleaned monthly. It would shake i think when it is off centered?
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Old 07-31-2020, 08:11 PM
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Quote:
Originally Posted by Sam View Post
Well, you have an impressive list of work done with replacements etc. I also vote for the installation of a liquid filled 0-15ps1 fuel pressure gauge and fitting between the carb and fuel pump [total about $35]. So far you have received a lot good logical advise and I would like to hear the results of running off an auxiliary tank. With a 1967 Cal 36 you have an early model A4 with the small Prestolite distributor [condenser screwed on outside]. If you would like to humor me pull the points plate from the distributor and check the springs and advance weights for proper function, even change springs [moyer] if they are original. Also, the little screw that holds/grounds the condenser may not be original and if the threads are a little too long they penetrate the housing wall and mess up the mechanism.

I have a friend with a restored 31 Chevy with a simple distributor with a manual cabal advance. The cable slipped and wasn't advancing the timing. The engine ran fine in neutral but bogged down under load [going up small hill etc]
Thank you, I think checking fuel pressure will have to be done.
On the other hand, originally I had a mechanical fuel pump when this problem started.

I replaced it with the electrical and it had no effect on it. Engine still slowly, gradually lost power after abut a minute in gear sarting at 1500 rpm.
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Old 08-01-2020, 01:29 AM
JOHN COOKSON JOHN COOKSON is offline
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THOUGHT OF ANOHER POSSIBLE CAUSE

After a shutdown check the temperature of the stuffing box with finger or a IR thermometer.

My posts R\E this problem are sort of disjointed I guess. My subconscious is working on the problem. When something pops up in my conscious mind I post. At least I think so.

ex TRUE GRIT
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Old 08-01-2020, 12:47 PM
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ah, the mystery...

Since it runs fine in neutral, I doubt this is a fuel restriction, but a fuel pressure gauge couldn't hurt. The way I understand it, if pressure goes down as it bogs down, you have a restriction upstream of your fuel pump.
Also, check the advance weights in the distributor. They could be rusted up and not moving well. Is your choke opening properly? If it stays closed that will also cause the engine to bog down. You may be running too rich. Stuck advance weights keep it from running leaner, if I'm not mistaken.
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Old 08-25-2020, 02:31 AM
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maybe the gears, contiued

Thank you capnward,

Interesting idea about the distributor weights. I opened it up and it was rusty as expected.
I cleaned it out, slightly greased it and managed to install two new springs.
It really looked like a sure fix for the advance in higher rpm.....
but again, it made no difference at all!
The engine ran about a minute and then gradually, very slowly the rpm was dropping and than it died like always.

Not sure what to do next? It's been over two years and nothing I have replaced, cleaned, fixed made any difference in either direction.
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Old 08-25-2020, 12:48 PM
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It's sounding more and more like it is fuel delivery related. This could be a lot of things but to eliminate the fuel to the carb a guage will give you an answer.

Dave Neptune
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Old 08-25-2020, 01:31 PM
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Quote:
Originally Posted by outoftheblue View Post
...
On the other hand, originally I had a mechanical fuel pump when this problem started.

I replaced it with the electrical and it had no effect on it. Engine still slowly, gradually lost power after abut a minute in gear sarting at 1500 rpm.
This still sounds like a fuel delivery restriction problem to me. I had something similar several years ago. Enough fuel gets delivered to keep the float bowl full and the engine running at idle, but under load, the engine consumes fuel at a higher rate than it is being delivered and the float bowl slowly runs dry in a minute or two.

In my case, it was the fuel pump, but since you've eliminated the fuel pump as a cause, the restriction must be elsewhere. The two places that come to mind are any "polishing" filter between the fuel pump and the carb, and the carb's float valve mechanism itself. But, back in post #1, you said you replaced both the carb and fuel filter!

That brings me back to the fuel tank and its pickup. But in post #12, you said you ran off of a spare tank and an electric pump and it still failed, although more slowly.

When you've eliminated the impossible, whatever's left, no matter how improbable, must be the answer.

So, what's left of the fuel delivery system that you haven't changed out? Hoses, fittings, elbows? Anything that could hold a blob of crud or a piece of teflon tape that could restrict the fuel flow. Really grasping at straws here.
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Old 08-25-2020, 05:10 PM
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Quote:
Originally Posted by edwardc View Post
This still sounds like a fuel delivery restriction problem to me. I had something similar several years ago. Enough fuel gets delivered to keep the float bowl full and the engine running at idle, but under load, the engine consumes fuel at a higher rate than it is being delivered and the float bowl slowly runs dry in a minute or two.
......


So, what's left of the fuel delivery system that you haven't changed out? Hoses, fittings, elbows? Anything that could hold a blob of crud or a piece of teflon tape that could restrict the fuel flow. Really grasping at straws here.
only way to rule that out is the pressure gage right before the carb. Do you have that installed? If yes, that would rule out the whole fuel chain.
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Old 08-26-2020, 01:27 AM
JOHN COOKSON JOHN COOKSON is offline
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Did you ever check the stuffing box? Post #15.

ex TRUE GRIT
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Old 08-26-2020, 11:37 AM
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Quote:
Originally Posted by Surcouf View Post
only way to rule that out is the pressure gage right before the carb. Do you have that installed? If yes, that would rule out the whole fuel chain.
Not quite true. A pressure gauge is a valuable tool, but a good reading doesn't rule out all types of fuel problems.

<Lecture Mode>

Pressure and flow-rate are two different things. Consider a pressure-washer. It has an insanely high pressure, but would take a really long time to fill a swimming pool!

Pressure, flow-rate, and restriction are related by an equation similar to Ohm's Law, where pressure is like voltage, flow-rate is like current, and restriction is like resistance. Thus pressure is proportional to the product of flow-rate and restriction. So, if the pressure remains the same, and the restriction is increased, the flow-rate has to go down.

</Lecture Mode>

True, the restriction would have to be downstream of the pressure gauge, which is why you should put it as close to the carb as possible, but there's always a few bits of hose and fittings after.

While this is all a fun intellectual exercise, it's a really low-probability possibility (I did say I was grasping at straws!).
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Old 08-26-2020, 01:23 PM
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I've been thinking how you can ease your mind about the reversing gear. Recommend the following:
With the engine off, remove the transmission cover. As you move your shift lever, you'll see the shifter cone around the main shaft move fwd (towards the engine block) and aft.
With the shifter in fwd, you should see the cone move AFT and engage the three fingers that engage the fwd clutch pack. The fingers should go over the hump in the cone and kinda snap into place. If this doesn't happen, your shifter is likely faulty/out of adjustment.
With the shifter in reverse you'll see the cone move fwd. It should almost come into contact with the notched ring for adjusting the fwd clutch pack. 1/32 or 1/16 of clearance is fine. If your clearance is more than this, try backing off the reverse adjusting nut a few flats and try again. If you can't get the cone to move this far fwd, your shifter is likely faulty/out of adjustment.
Take some pictures if you see anything questionable. Hope this helps.
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Old 08-26-2020, 11:08 PM
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Check all connections in the fuel lines. Years ago I was not leaking fuel out, but air in and she would die out after time
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