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engine failure

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Moondocker
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engine failure

Post by Moondocker » Sat Aug 13, 2016 8:11 am

What would cause a fresh rebuilt KLC to consistently quit after reaching 2200 rpms? Fuel delivery and ignition has been ruled out. Boat will reach this point and then falter and die off after about a minute and a half of struggling. Owner claims a "burnt oil and some engine noise" (knock?) before it finally quits. The engine immediately restarts and does this all over again. The boat runs fine at 1500 rpms but once it is pushed, under a load the aforementioned conditions, it quits. Carburetor, fuel pump and ignition systems have been rebuilt.
Thoughts?

jim g
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Re: engine failure

Post by jim g » Sat Aug 13, 2016 4:19 pm

Whats the oil pressure at when it quits? What is the engine temp at when it happens? Was the oil pump rebuilt? Will it go past 2200 before it dies out?

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DennyDowning
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Re: engine failure

Post by DennyDowning » Sat Aug 13, 2016 10:09 pm

Boy does that sound kinda like some of my issue. Starts right back up too hugh.... Yep. Well if it was just rebuilt then that might explain the oil smell. You say fuel and ignition are ruled out. But I wonder how you can rule that out. On my boat people swear it is fuel but then why would it start right back up. Tough to call. I am no expert and will state that right up front. But, the coil output probably increases at higher speed and there could be a shorting situation going on when the energy increases. Would be interesting to try operating at night and do the water spray and see if any arching occurs.

Be calm and start with the easy stuff. Condenser.... What kind of ignition wires? Solid Copper? Coil, Distributor? Then you might consider the carb as higher speed uses more fuel.... Float Adjustment or sticking?

I know you have ruled out ignition and fuel but just checking.

Vacuum leak.... Fuel Filter, Pump.....

At least it is consistent.
Please let us know what you find.

Denny
Last edited by DennyDowning on Mon Aug 15, 2016 9:48 am, edited 1 time in total.

Moondocker
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Re: engine failure

Post by Moondocker » Sun Aug 14, 2016 6:37 am

2000-2200 rpms is the best it can do before it starts to die. At 1000 plus rpms, oil pressure is excessively high, over 60 lbs I am told. Engine temp is unknown and I do not believe the oil pump was rebuilt. The wiring harness was bypassed and the coil was powered directly from the battery. Nothing was said about timing the engine. The owner is at the point of pulling the engine and sending it back to the rebuilder. I just am not convinced that it is an internal problem. In addition, when the motor starts to die out, he claims that pulling the choke to fatten it up does nothing.
Thanks for your input guys.

jim g
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Re: engine failure

Post by jim g » Sun Aug 14, 2016 8:48 am

Timing needs to be checked. If its to far advanced you won't get full rpm's and you will get ignition rattle. Which to some people can be a knocking sound.

What ignition system is it running? If its the 6 volt pertronix in the small distributor put points in it.

Also if it has the adjustable high speed jet on the carb. Try opening it up. Turn it counterclockwise from the rear.

To me it sounds like the timing is to far advanced or that its running lean. Its Probably both. If this is it and depending on how much he has been running it like this. He could have damaged one or more of the pistons. Running lean increases the the cylinder temp. to the point it can start to melt the piston.

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DennyDowning
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Re: engine failure

Post by DennyDowning » Sun Aug 14, 2016 8:53 am

Oil pressure sounds great. No problem there. Definately sounding like fuel and a frustrated owner. The noise it makes before dieing is probably just the transmission slapping around. Pulling out the choke????? Why? Is the owner able to put a fuel pressure gage on just before the carb to watch fuel pressure?

Denny

Greg Wallace
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Re: engine failure

Post by Greg Wallace » Mon Aug 15, 2016 8:36 am

Unless I missed something there was no mention of cooling system check. "No temp gauge" stated. The "noisy" shutdown suggests it might be overheat seizure. Another possibility is might have been put together a little too tight during recent rebuild with similar symptoms as temp comes up. I would confirm is cooling and get a temp reading.
Greg Wallace 23 Custom 22166 former Chris-Craft dealer Russells Point, Oh.

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DennyDowning
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Re: engine failure

Post by DennyDowning » Mon Aug 15, 2016 9:34 am

Hmmm... Interesting.... I am curious now. It seems to me that if the engine was overheating and seizing that it would be difficult at best to immediately restart as stated. If I am wrong here I would love to know as I am not an engine guy but years ago I had an engine, in a car, overheat and seize. It sure did not start immediately back up.

It was stated that fuel and electrical were ruled out. I read that. But an immediate start up and run fine up to the same RPM again and again before a fail. Can that really be overheating? The reason I would like to know is because I have a stall problem I have been trying to solve. If overheating is the issue, I have no temp guage, I would inspect for that. I assume that an overheated engine would have to cool some before immediately restarting and running fine. Guess I am not to old to learn.

One of my problems was the ignition shorting out. The sound from the engine, as stalling, made my heart sink as it sounded like it was really broke; like a part failed and the engine was a goner. But the noise was from the transmission as the boat was still in gear and the RPM's were falling and the prop was basically causing the engine to turn. Really sounded bad like when the RPM's are to low. Turned out to be a burned back coil wire. I had used the wrong type of ignition wires. Again, no expert here. but I was told the new resistance type wires will fail, at least on my old girl, and that I should use solid copper wires.

That being said. I still have curious occasional stalls but the wires are ruled out for sure now. Not sure about the shorting in the cap however.....

Anyway, sorry if I am barking up the wrong tree here and hope I am not being a pain..... I really would like to know if an overheat condition that caused a motor to stall would allow the engine to immediately start up again and run just fine at a little lower RPM but stall again when reaching the higher RPM and do it consistently over and over again. Could be helping out a few people here.

Denny

Greg Wallace
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Re: engine failure

Post by Greg Wallace » Mon Aug 15, 2016 10:02 am

I would normally not expect a quick recovery from overheat seizure. (I missed the comment regarding immediate restart).

That being said stranger things have happened.

It only makes sense to rule out cooling as an issue....I check the pipe for water on every start up.

Its a long shot but if cooling issues remain suspect I would also check for even cooling (temp) on the various areas of the motor and manifolds to ensure no blockage and isolated hot spots that could cool down rapidly allowing for the rapid restart.
Greg Wallace 23 Custom 22166 former Chris-Craft dealer Russells Point, Oh.

Moondocker
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Re: engine failure

Post by Moondocker » Mon Aug 15, 2016 1:46 pm

Thanks for all the good input but it doesn't matter at this point, the engine was pulled and sent back to the rebuilder this morning. The owner was convinced that all avenues were exhausted and it can only be an internal problem. If you all like, I can let you know if/what is found once it is torn down.
Thanks again.

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quitchabitchin
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Re: engine failure

Post by quitchabitchin » Mon Aug 15, 2016 1:57 pm

I would look at the float setting in the carb. That could cause the bowls to run dry at said RPM's where they keep full enough to stay running at lower RPM's and would start back up fairly easily.
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DennyDowning
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Re: engine failure

Post by DennyDowning » Mon Aug 15, 2016 3:09 pm

Well Okay MoonDocker.... I got a feeling the engine is just fine or it would not have started so easily and run so nicely at lower RPM's. But at least you tried and I think (bet money on it) you are right the engine is fine. Starts right up and runs great. Every rebuilt engine is going to have some smell till it burns off the oil and fresh paint and sealers and such and a stalling engine at those RPM's is going to make some ungodly sounds especially if still in gear when stalling. Guess I feel kinda bad for the owner because he should be out boating; but boating often require's patience as well. Not saying that engine rebuilders do not make errors as I know they do......

Nice try to save the owner more frustration but sounds like he is just getting started. Dang....
When I think of all the work pulling the engine again when it could be a simple carb adjustment. Double Dang....
I always think FUEL and SPARK. But you guys ruled that out to start with????

Reminds me of my brother - he rebuilt the carb on his 1965 mustang. And after that the car just would not get to the high RPMs it should have and started running very rough at higher RPM's. I was with him when he took the car to an engine expert and the guy said it sounds like the Carb and my brother said it cant be the carb because it was just rebuilt ~ to which the guy replied now I know that is what it is. Turned out the four barrel gasket between the carb and the intake manifold was installed backwards. small and large gasket holes were reversed.
Ha, and my brother totally ruled out the carb.

Denny

Moondocker
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Re: engine failure

Post by Moondocker » Mon Aug 15, 2016 3:48 pm

I tried my best to convince him it could be a simple issue but he had someone "check everything" and they could not get it to run right and his conclusion was that it is an internal problem.
We shall see.

Moondocker
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Re: engine failure

Post by Moondocker » Thu Aug 18, 2016 3:52 pm

Just an update. The motor was torn down by the rebuilder. What was found was "scuffing on each piston" and bearing failure. The crank is ok. I have no idea what happened. Whether it was bad work by the rebuilder ( he has a very good reputation for rebuilding old motors) or the owner did something ( low/no oil or did not follow a break-in procedure). Nonetheless, this was where the problems were.
Thoughts?

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mbigpops
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Re: engine failure

Post by mbigpops » Thu Aug 18, 2016 8:54 pm

Dry bearings are a sign of insufficient oil pressure most likely caused by low oil level or faulty oil pump.

See if they can test the oil pump manually before they put the engine back together. Also, if you run out of the boat make sure that you have the engine at the proper angle and the oil level is where it should be.

When you do start it up again watch the oil pressure gauge like a hawk and shut down if you don't have good pressure.

Mark
1953 CC Rocket Runabout "Rocket Man"

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tkhersom
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Re: engine failure

Post by tkhersom » Thu Aug 18, 2016 9:00 pm

As with the carburetor story, ALWAYS suspect the last thing touched by human hands.

If the oil pressure was higher than normal (I don't know what is normal for this engine) I would suspect the tolerances were too tight when the engine was put together.

It is so easy to be an armchair quarterback.
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Moondocker
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Re: engine failure

Post by Moondocker » Fri Aug 19, 2016 7:55 am

The oil pressure was 60 lbs which is ok at cold start up but I was told when the engine started to stall out it was still 60 lbs. I believe that you are correct in saying that the tolerances were too close. I am going to suggest the builder replace/rebuild the oil pump. Have you guys ever seen these pumps fail? It's been my experience that they are pretty much bullet proof. In fact, I had a 4 cylinder Hercules rebuilt ( in a 1945 farm tractor) and that pump had never been replaced or repaired and it still delivers good service today.

jim g
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Re: engine failure

Post by jim g » Fri Aug 19, 2016 5:13 pm

Moondocker wrote:The oil pressure was 60 lbs which is ok at cold start up but I was told when the engine started to stall out it was still 60 lbs. I believe that you are correct in saying that the tolerances were too close. I am going to suggest the builder replace/rebuild the oil pump. Have you guys ever seen these pumps fail? It's been my experience that they are pretty much bullet proof. In fact, I had a 4 cylinder Hercules rebuilt ( in a 1945 farm tractor) and that pump had never been replaced or repaired and it still delivers good service today.

Yes. I have seen them loose pressure. They don't break. But do get worn inside.

One thing that could have happened is. If the engine was not primed with a pressure pot and they were relying on the oil pump to build pressure when the engine is first started after the rebuild. Will cause damage to the bearings. These pumps don't prime very well. Especially at there age and the wear they have on them.

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