Believe I have stuck exhaust valves. Still have a question

[msauntry]

Seeing as the engine ran fine a short while ago, and then has episodes of poor running, I'm inclined to believe you don't need a head job.

Have you ruled out two things? 1. Exhaust backpressure 2. Fuel clogs

If the exhaust system gets clogged, it can run better on three cylinders than on four since the extra air from the fourth can't squeeze through. If you're about to do head surgery, pull the exhaust off first and do an autopsy on it.
Watch Beverly Hills Cop to see what effects a banana in the tailpipe has on Taggert's car.

Why have you ruled out fuel? I noticed you had success after priming the bulb in the beginning. Perhaps that cleared out some clog but another has taken its place? I'd clean the carb out and try again.

Before this happened did you see any signs? No oil in the water, no water in the oil, no smoking exhaust noted, valves seem functional, no exhaust fumes noted in the engine compartment...

[MikeB.330]

David,

I'm not an expert but maybe a fresh set of eyes and ears may be of some help. I live in Crownsville so I'm not far from your boat.
Let me know, I'm more than willing to take a peek at your engine.

BTW: I also race (trying to learn anyway) with RBSA. I have the old black Pearson that hardly ever finishes before TLE..

Mike

[P30_889]

Love to have another set of eyes

Regarding the other questions:
1. the plugs and wires are less than a year old
2. I have tried using 'new' gas and the behavior is the same
3. I am going to look for blockage in the exhaust and see what else I can find.

Mike-
I am heading down to the boat this Wednesday (hoping to get out somehow to race on Wednesday) and would love to have another set of eyes on the boat. Please email if you are available. If Wednesday isn't good just let me know when might be good for you and we will go from there.

David Hagler
dshag1@comcast.net

[P30_889]

Strange but true (I have witnesses) Still don't know what to do

I am at a loss what to do with the engine but last nights events give me a little hope that there might be a simpler answer to my current engine problems:

The most current events are:
1. Two weeks ago the engine started, ran really rough (shut down because it ran so poorly)
2. Last week it started up and ran fine (a little rough initially but then ran fine)
3. Four days ago, no life at all when trying to start. (only tried for a minute or two and just sailed in/out of the slip.
5. Yesterday, started up on the second attempt to start. Ran rough for 4-5 mins (backfire, no power -yet good water flow out the exhaust) then like a switch flipped and the engine went right up to full power and ran smoothly for the next 20 mins or so with no problems at all.

Someone on the boat asked if I had looked inside the distributer. He thought maybe the timing advance springs were maybe bad or something.

Am I overlooking something really simple ??

David Hagler
Pearson 30
Annapolis, MD

[Kurt]

During my last round of engine power problems, a neighbor of mine who calls himself a marine mechanic looked in my distributor and told me that my advance was messed up. He also hooked up a timing light to "determine" this problem. We oiled the springs and no change. I bought a new distributor - no change. Point here is that these distributors are REALLY robust and VERY simple. Basically, if you can push the rotor to one direction (I forget what direction, but it only goes one way) and it snaps back, your springs and advance are probably just fine. That's how you might want to rule this issue out. My problem turned out to be an exhaust restriction in the hot exhaust area that necessitated an entire new exhaust system. Your reported no compression at times is a headscratcher in light of the fact that the engine runs fine sometimes. You might want to spend $30 on a compression gauge to determine once and for all exactly what your compression is on each cylinder. Automotive stores have 'em and they are a nice diagnostic tool for these engines.

[ghaegele]

David,

Something in one of your earlier posts caught my attention. It's the horrible metal on metal sound you experienced when these problems began.

A few years ago I had a confounding problem that ended up being broken valve springs in cylinders 3&4. Initially I diagnosed stuck valves by a finger test. I squirted Mystery Oil in there and pushed the valves down with a bent screwdriver and cranked and when I tried compression testing they were fine--110 psi. But still the engine was running rough and under load or revving, I was getting no power from no.s 3&4. Finally, I put the compression tester on the cylinders with the engine running and revved it and the compression dropped to zero as the RPMs rose. It seems the valves were dropping down under their own weight and creating compression when run by the starter motor or at idle, but not when the RPM's were high. When I pulled off the valve plate everything looked fine, but when I touched the springs I could see that though they appeared fine I was only looking at a few pieces of spring. The rest had fallen into the bottom of the valve access.

While I recognize your problems are almost opposite, the kicker is that all of my problems started after the season start up when the engine was running perfectly, then suddenly there was a horrible metal on metal noise. Check those valve springs!

Good luck, Greg Haegele

[P30_889]

Many thanks to those who responded. I am without a computer for awhile

My computer blew up over the weekend so I couldn't respond to the posts. Thanks so much for the story of the valve springs. I just raced my last Wednesday night race in Annapolis and my goal now is to get the motor running so I can enjoy the fall season here in Annapolis.

Cheers,

[P30_889]

Found the problem. Now looking for best solution

I almost have my home computer back up to speed. In the mean time I am taking a coffee break to update this thread.

Well I found two sticking valves. The intake valve closest to the flywheel and the second from the end (non flywheel side) exhaust valve. Along the way I have discovered that the carb is in desperate need of cleaning and that the exhaust manifold must not have been sealed against the block. (There was discoloring on the outside of the manifold near the non-flywheel side and my wife always complained of exhaust smell in the cabin after the engine ran.)

It appears that I was able to run at times because these valves must have somehow become 'unstuck' at some point which allowed my engine to run (at times very well) but then at other times not start.

Should I just pull the engine and do a valve job or try to do the valves or just 'unstick' and clean the valves while it is in the boat?

Is it possible to just 'unstick' them and then have everything be ok? This problem has been going on now for about 2 months so I am not really happy with the thought of a temporary fix as it has not helped up until this point.

I am going to check the exhaust for blockage (but it is less than 5 years old with only a few hours on the exhaust system.

[P30_889]

End of the saga for now. (From back this fall)

Well thanks to all who posted replies about my issue. (My computer blew up and I was away from the site until March or so).

It turned out I had two sticking valves (exhaust). I pulled the engine, took it to a local engine shop (they build engine for race cars and dragsters). The folks there were great. The did a valve job and re-machined the head and block, cleaned it up and re-assembled the whole thing (including paint) for less than paid a local company to give me a tune up/oil change two years ago.

It was slow, but kind of easy to get the engine out of the boat. I had it over the winter and rebuilt the carb, cleaned the exhaust manifold and fixed up some problems with the manual fuel pump.

The crew helped me put the engine back in the boat. The hardest part was getting a freeze plug back in the block (the one behind the starter). My friend came over and re-tapped the hole and got it back in. I put all the pieces back together.

She started on the first try without the choke! She ran better than she ever ran before (I have only had her for three years but she always stalled but ran fine under full load until my problems started last summer). Seems like all is good for now. She is really pretty sitting there in her mounts. No vibration at idle and no stalling when going from forward to reverse! I tried adjusting the idle on the carb but she liked it right where she started. I never even bothered to make timing adjustments since she ran so well.

Thanks to Don and the forum for all the help and encouragement! It was a great experience and hopefully I will have good season with her this year. I also attended the spring 'training' in Penn. last year which was a HUGE help once I got to taking all the pieces out and messing around.

P.S.
The only problem I had was one time she stopped drawing water into the engine for about 2-3 mins. I noticed the temp and the lack of water and shut her down. I pulled the thermostat and started her again after a rest and cool down and she ran a little cool (110-120) but the water was going through the system fine. Not sure what to make of that. I did install the Moyer space and used the less expensive thermostat. I checked the therm at home and she worked correctly (Opened when she should have) so I am not sure why they system couldn't get water through it with the therm in.)

[Marian Claire]

The new thermostat I installed did not function properly on the boat. It would stick open some times and then not open at all the next time. It worked fine when tested in a pot of water. I ended up removing it and using a ball valve to control the flow. I can get her to run at any temp I want. If you try this the valve should be installed in the line from the engine to the exhaust. Dan S/V Marian Claire

[Jesse Delanoy]

Dan,

Just to clarify, you have removed your thermostat, and installed a ball valve in the hose that runs out of the rear of the manifold and into the exhaust (water lift muffler)? I may give this a try, as I'm still trying to come up with a good way to run hot water into my hot water heater core. I tried Don's method of criss-crossing hoses, so as only to get engine heated water to the heater core, and running bypass water directly to the exhaust, but the engine overheated unless I shut down the bypass entirely, and then all I got was steam out of the exhaust.

If I can take out the thermostat (which will make the engine run cool) and use a ball valve to warm it up to a selected temp, that might work out well.

Jesse Delanoy
s/v Off The Grid (nee Agape)
Baltimore

[Marian Claire]

Yes. My A-4 is an early model, raw water cooled. Very simple, one line in one line out. By restricting the flow out I can run her from below 100 to too hot. I set an oven thermometer on the head just to double check. When the engine is warm, water temp 150+- the head is at 175+-. Make very small adjustments until you get the right temp. Hope that helps. Dan S/V Marian Claire

[marthur]

If you stopped pumping water and then the motor ran cold it could be the thermostat. It could also be a piece of something that blocked the water line, then moved on to block the bypass.

We had that happen to our motor. The blockage was a piece of an old impeller pump. Must have been in the engine for years since we have always replaced the impellers before they fail.

Good luck!

[P30_889]

Very bad news after just 15-20 minutes running

My rebuilt (not Moyer) engine slowly stopped running today after no more than 1 hour of running. She was find initially, then slowly over the course of the last 40 minutes she started hesitating a little bit, then finally lost power and started backfiring and then just wouldn't start. I went from good compression all around to only compression on cylinder #2. This is very frustrating. She seemed like a good rebuild and started right up. Not sure where to go from here. I need to check the clearance on the tappets and see if somehow I can get compression again.

[sastanley]

David,

Sounds like we may be starting the troubleshooting from scratch.

Don't worry, we'll all do what we can to help. I've done tons of work on my motor this past winter and it is still on jackstands!