Believe I have stuck exhaust valves. Still have a question

[P30_889]

Don,
I attended your seminar this spring and called you about a week ago about a coil for my Atomic-4. It appears that my exhaust valves are stuck and I am planning on attacking the problem tonight.

Here is a quick question for you if you don't mind:
Can you explain why I was able to run the motor last week (it took awhile but it did start). The engine ran fine for the 20 mins or so it took me to get out to the race course. I then was unable to get the motor started again and that is when I determined it was related to the exhaust valves.

Is it possible for exhaust valves to get unstuck just from trying to start the motor for quite a while? I was trying to start the motor for 20+ mins before it did finally start.

1. This whole year I do NOT open the raw water intake until the engine starts
2. The most recent time, the engine ran fine although there was some awful 'metal on metal' sound in the engine for 10-15 seconds then went away and the engine ran fine

I plan on trying to free up the valves via the top of the cylinder today. If that doesn't work I plan on getting to them via the side of the engine and finally via the head if that is necessary.

Any other recommendations?

David Hagler
Pearson 30
Annapolis, MD

[Don Moyer]

David,

The simple answer to your question relative to exhaust valves is that they definitely do not normally unstick simply from cranking for a while.

This reply of course leaves unanswered the question of why your engine did not start. If an engine won't start in the first 15 or 20 seconds of cranking, it is usually best to troubleshoot and determine why. This would involve the process of pulling the coil lead out of the center of the distributor cap and checking for a secondary discharge to the head or block, removing the flame arrestor to check for raw fuel puddling in the intake throat of the carburetor, and lastly, a thumb check of each spark plug hole for compression.

Did you try a thumb check of your compression to determine that the exhaust valves were in fact sticking? If your exhaust valves really were sticking, they must have been sticking very, very lightly and literally fell down and began working after you cranked for a while, which doesn't seem very likely.

Don

[P30_889]

I know it is hard to believe. Here is what happened

I know it sounds crazy.
Here is what happened:
All of a sudden the motor took a long time to start. I put a priming 'bulb' in the fuel line to help get fuel to the carb to help start the engine more quickly. (Problem solved I thought. The motor started right away (or close to it) once I primed the fuel system.

Recently it was not starting even with the bulb. Two weeks ago it took a long time but it did start and ran fine.

Last week it didn't start at all. I checked the compression and there was NO compression on any cylinder. I am hoping that all I have to do is tap down the valves but it literally went from running fine to nothing in that short of a time period.

I hope the engine can be revived.

David Hagler
P30 Annapolis, MD

[P30_889]

Strange things keep happening (don't know what to do now)

It must be me!
Background: My engine ran great for the time I have owned the boat (coming up in two years). Last year someone 'tuned' it up for me. Since then it hasn't run as well.
Recently: Wouldn't start and I had a bad coil. Replaced the coil and the engine ran well.
Engine stopped running again so I did a compression test. 0 compression in all four cylinders. I assumed it was exhaust valves. Don mentioned it was more likely intake valves (he has never seen all four exhaust values stick from water coming into the engine). And reading his manual I did come across his comment saying the same thing.

Don recommended using a dowel in the cylinder to test if the intake valves were moving. I did this last night. Result:

1. Three of the four valves did move when the engine turned over. The valve on cylinder #1 did move once, then I didn't really feel any movement. Each time I initially turned over the motor I did feel something.
Then out of nowhere -
2. The engine started. I don't know how, but after 4+ mins trying to get it to start it finally did start. (I kept trying because I could tell from the sound that the engine wanted to start)

It appeared to run rough initially, but after a couple of mins the engine was smooth and running fine. Then after about 15 mins of motoring the engine just died without warning (we were getting ready to start the race so not a big deal). I tried a couple of times to start it with no luck. I didn't keep trying.

I don't know what to do here. I am considering pulling the motor and doing an overhaul. (Feeling like there must be SOMETHING going on here). I don't mind trying to trouble shoot issues, but it seems to be a different thing each week and I find myself not going out on the boat as often because I am worried about the motor starting.

Here is my question to those who have pulled/worked on the motor:

What is a reasonable amount of time to expect to pull the motor, get parts and have things fixed and then re-install the motor? I realize a big part of the time has to do with me doing the work, however, if I need parts or machine work done, do people turn these tasks around in hour/days or weeks? I wouldn't mind giving up the boat for August and working on the motor if it meant that I would have it for Sept-Nov/Early Dec as those are great months to sail. However, if this is a really long process, I will just wait until the early fall, pull the boat and make it a winter project. Any suggestions?

[Marian Claire]

Time

I just rebuilt my A4 this spring. Six weeks from start to finish. Lost a week with the machine shop due to my order error and the fact that they where moving at the time. All times are +_. Remove 1-2 days, disassembly 2 days. Shop time 2 to 3 weeks. Cleaning and reassembly 1 week. Bench test 1 day. Reinstall and adjust reversing gear, drive shaft etc 2 days.
Moyer can get you parts in about two business days, so try and order before Wed. Good luck. Dan

[Don Moyer]

Dave,

The fact that your engine runs so well when it does start is clear evidence that it does NOT need a general overhaul.

Frustrating though it is, you must continue to methodically diagnose these mystery shutdowns and especially these episodes of total loss of compression on all cylinders one day, and then miraculously running OK the next.

Try to reach me by phone again. We need to come up with a diagnostic strategy.

Don

[P30_889]

Still with a question

Don,
I will try to call you on Monday. I know it sounds crazy and I am not discounting the possibility that I am overlooking something really simple during this whole episode. It is possible that I messed up my compression test, but I was able to easily put my thumb over the spark plug hole and I tried each cylinder twice when I determined that there was no compression. While at your workshop I used one of your demo motors to feel what 'good' compression feels like so I think I have an idea of what to expect.

Anyway- the good news is that someone donated a old A4 to me and I took it down almost all the way to the block on Saturday. While I still have my issues with my other engine, at least I now have more comfort with the engine overall and if I need to get into the engine on my boat, at least I now have taken almost all the major components off the 'donor' engine. (As always happens to me, there was one bolt (accessory drive bolt under the water pump) that won't come loose so that is still attached. Everything else came off without a problem.

David
Annapolis, MD
Pearson 30

[Baltimore Sailor]

I once had zero compression on all my cylinders this past spring. It turned out that my gauge was bad. I'm pretty sure that even with all the valves stuck open you'd get some kind of reading above zero in the cylinder.

[P30_889]

More interesting happenings with Engine

Re: Compression testing - I did the 'thumb' compression test, not a measured test. I didn't do a good job explaining what I was doing so I apologize. It was a thumb test (thumb should be pushed off cylinder and I didn't fell anything (granted, this was my first time trying this test so I might not have been savvy enough to pick up on the difference in pressure under my thumb.

Tonight I was on the boat and she started up on the first or second attempt. (Hasn't done that in a few months.) She was running rough but was did run (at idle, not under load). We had a theory that she was running rough due to lack of combustion on one or more of the cylinders. While the engine was running we started pulling spark plug wires. When we pulled #1 then #2 (one at a time) you could tell that the engine was feeling the effect and ran a little more roughly. When we pulled the plug wires for #3 and #4, there was no noticeable difference in how the boat ran. It appears that I am running on just 2 cylinders. (Unless there is an explanation why the engine would not change its behavior by pulling wires 3 or 4.)

I pulled the valve cover and the valves are moving up and down on #'s 3&4 and there is spark. I stopped then started the motor up again and she sputtered along fine. (Rough, but able to run). I did notice that the oil pressure was higher after taking off the valve cover and then putting it back on. Originally when the motor was just above an idle the pressure was 32psi and when we pulled off then re-installed the valve cover the pressure was more like 40. Odd but I am not sure what if anything that means.

I added a little more MMO to the engine. I am putting my fall plans on hold and hope to finish out my Wednesday night racing until I can come up with a plan of action.

[tenders]

> (Unless there is an explanation why the engine would not change its behavior by pulling wires 3 or 4.)

If your wires and plugs are OK, I think you have a blown head gasket between cylinders 3 and 4.

[P30_889]

Great insight

I will pull the head in the next week or so and see if that is indeed the case. I didn't see water in the oil so I discounted the head gasket, but I guess that would make sense that it is possible. Thanks much.

[P30_889]

Getting worse. Now it barely idles

The motor started last night but it had no power and was barely able to get out of the slip and into the river. Don't know what is up now. Time to dive in and find out what is up.

[tenders]

Get wet if you want, but with no compression in two cylinders I'd get dirty and pull the head before I got wet.

Edit: sorry, I thought when you said "dive in" that you had received signals from space telling you that this could be a prop or shaft problem.

[P30_889]

You are correct Sir! Head about to come off.

Knowing this isn't just a run of the mill issue anymore but a full blown 'problem' here is my plan:
1. start taking apart the pieces (check exhaust to see if clogged)
2. pull head off motor and check for head gasket
3. if nothing is obvious, start taking apart and get the pieces worked on as I go.

[rheaton]

You might want to try to first replace plugs and/or plug wires. This made a difference on my engine. Good luck.