H 34 no power above 2800 rpm
- Thread starter hunter healer
- Start date
Today I experienced the overheat lite buzzer sounding after 30 minutes @ 2800 so I shut down the engine for 30 min then attempted to start and it took 3-4 try's so I advanced the throttle after 10 seconds buzzer shut off and lite went out and I have been motoring @ 2000-2200 for 1.5 hours with no buzzer it lite's coming on? I can't figure this one. Changed impeller, thermostat and did a visual on heat exchanger from both ends with end caps off inserting a coat hanger in all the holes no sediment or blockage so replaced all gaskets and topped off antifreeze. Water flow out exhaust is present. Changed primary fuel filter on engine no leaks and cleaned raw water strainer? Ideas
Check the exhaust elbow for partial blockage from built up carbon. I had this same problem no power and I could not get over 1000 RPM.
YOu may not be looking at the mixing elbow. The internal passages are about 2" dia. for the 2GM (which I think you have). You don't need to cut in half to inspect for corrosion but you do need to check the archives here for the correct procedure to remove this little beast. It involves both LH and RH threads. A bit of homework, but will save BIG $$$$$$$$$$$$$.
Here's one with a few extra pieces attached to it.
Attachments
Most 34's were delivered with Yanmar 3GMF's.. some of the earlier ones had a 4 cylinder Westerbeke.. I am assuming a 3 GMF.. and the elbow that Ralph shows is exactly as on the 3GMF.
Not 100% sure, but I think the elbow has left hand pipe threads and the part that bolts to the engine has right hand pipe threads.. Most folks take it off by removing the 4 bolts that hold the part bolted to the engine. You can kinda quickly inspect by pulling the big hose off and using a mirror and flashlight to look up. you should see kinda clear passages as in the left side picture.
Not 100% sure, but I think the elbow has left hand pipe threads and the part that bolts to the engine has right hand pipe threads.. Most folks take it off by removing the 4 bolts that hold the part bolted to the engine. You can kinda quickly inspect by pulling the big hose off and using a mirror and flashlight to look up. you should see kinda clear passages as in the left side picture.
A close of my old photo shows Kloudie has perfect recall (and that's scary
) on the location of the left and right hand threads. Be sure to use a parting compound when re-assembling these parts as they should be pulled apart and checked periodically.Attachments
And That's the Way It Starts .......................
First it's partzheimer's, then it's somezheimer's, and finally allzheimer's.
I've GOT to find my keys this morning.
......................... remember the long past stuff like it was yesterday but the recent stuff, not so much.
First it's partzheimer's, then it's somezheimer's, and finally allzheimer's
.I've GOT to find my keys this morning.
Well, I removed the mixing elbow, along with the manifold adapter and the exhaust hose on the other end. It was easier to disconnect the hose from the muffler and remove it all as an assembly. I bought some muriatic acid to soak the elbow over night and hope to reinstall tomorrow.
I have been limited to 2800 RPM for the last couple years, and thought I had a throttle linkage problem. This thread and some encouragement from John Moffit of Red Dragon have caused me to seek to remedy this issue.
I have been limited to 2800 RPM for the last couple years, and thought I had a throttle linkage problem. This thread and some encouragement from John Moffit of Red Dragon have caused me to seek to remedy this issue.
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Using a half gallon of muriatic acid from Lowes and 4.5 gallons of water in a 5 gallon bucket, the assembly soaked overnight. I couldn't get the exhaust hose off, and it made a good handle to periodically stir the parts in the solution. This morning the solution was a cloudy green with soot particles on the bucket bottom. I rinsed and flushed with water from the garden hose. I will install hoping the problem is corrected, but will next clean the heat exchanger even if I get 3600 RPM in neutral.
Reading further last night, it seems the consensus is to replace the elbow as a consumable. Apparently, corrosion from the inside eats through the elbow. I think a good bet would be to soak the parts every couple years and replace when necessary. I will get one of those muffler patches to keep on board as an emergency band-aid
Reading further last night, it seems the consensus is to replace the elbow as a consumable. Apparently, corrosion from the inside eats through the elbow. I think a good bet would be to soak the parts every couple years and replace when necessary. I will get one of those muffler patches to keep on board as an emergency band-aid
Get a new one.You will be glad you did.It's peace of mind and a cheap reliable fix.You can always save the old one for emergency, if you don't have a new backup.
Remember the threads are reverse when removing from manifold.I just hit once with a large hammer.Then it falls right off threads.You will be amazed.Those things are made of cast.Easily destroyed.Forget trying to fight to get it off by unscrewing.Then clean threads.
Remember the threads are reverse when removing from manifold.I just hit once with a large hammer.Then it falls right off threads.You will be amazed.Those things are made of cast.Easily destroyed.Forget trying to fight to get it off by unscrewing.Then clean threads.
Well, after reinstalling the exhaust adapter, elbow, and hose I was again unable to get above 2800 RPM like "hunter_healer". Either the soaking in solution was ineffective or the elbow wasn't the issue. I am betting on ineffective muriatic acid solution and ordering a new elbow. I will clean and keep the old as a spare.
I needed to get some anti-seize for the installation and got a muffler patch to keep on board for a catastrophic failure bandage. I hope it works if I need it.
I needed to get some anti-seize for the installation and got a muffler patch to keep on board for a catastrophic failure bandage. I hope it works if I need it.
There's no doubt about it, carbon in the mixing elbows is just one step short of turning into diamond. I once tried an oven cleaner called "Oven Off" and had very limited success. Nothing else other than hours of scratching away at it seems to accomplish very little if anything. At that age, I'm sure you were in the market for a new elbow.
Let us know if you get over 2800 with the new elbow. If not, it's back to the drawing board.
H 34 3GM30F limited to 2800 rpm
I am thinking it might be a failure of the governor or injector pump unable to supply fuel at the necessary pressure to get above 2800 RPM. It is very strange that hunter_healer and I are both limited to 2800 RPM with no other symptoms. My engine sounds great after the muriatic acid soak of the exhaust elbow, and has power, but the throttle will not take it past 2800.
I am thinking it might be a failure of the governor or injector pump unable to supply fuel at the necessary pressure to get above 2800 RPM. It is very strange that hunter_healer and I are both limited to 2800 RPM with no other symptoms. My engine sounds great after the muriatic acid soak of the exhaust elbow, and has power, but the throttle will not take it past 2800.
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