2GM20 Exhaust Elbow
It has been suggested in the past on this Forum that the exhaust elbow on Yanmar 2GM20 engines should be removed and checked for erosion once a year, and as I have the engine out at present (to replace the engine mounts and engine bearers) do you think it would be a good idea to take it off and check it?
There is no evidence of water leakage at the moment and it works fine, the bolts do look quite rusty and are solid, they could possibly shear off on trying to undo, but this would be accessible at present, if I encountered any problems.
Not so in the future, it could be quite difficult to replace once the engine is re- installed.
Question: Should I not look for trouble and leave well alone as there is no present problem, or should I check and maybe encounter problems but which would be easier to sort out now rather than later?
What would the experienced do?
I am not experienced with inboard engines as this is my first inboard set up and I am endeavoring to get it all right prior to re-installing it.
I have already had the Injectors serviced, and replaced the Thermostat, Oil and Temperature Senders, all the Fuel hoses and s/s clips and intend to fully service the engine buy replacing all the Fuel filters and Oil filters, also replacing the Water Pump Impellor, and changing the Engine and Gearbox oil and Filters as a matter of precaution as I am unaware of its Service History?
My experience to date is with a fin Hurley 22 which had an outboard which I had for 10 years. I have now moved up to a 1974 Hurley 30 which is a whole new ball game and it appears I have a lot to learn about lots of things!!
Any advise welcome.
(Sorry its a long thread)
If you've got the engine out it is a simple job to remove the elbow and I would certainly check it. It's a lot easier than when the engine is in place.
While ensuring the bolts are free while they are accessible is a good idea, checking the elbow can be done simply by examining the inner pipe. If light from a torch shone down the water inlet pipe is visible through the inner, replace or get a new inner tube welded in (considerably cheaper!). Of course, if there is no inner pipe then it's knackered.
Yes, check it now. Just think how you'd regret not having done it if it fails during the season! If it needs replacing, just make sure you're sitting down in the shop when you go to get the new one.
I would remove and inspect the elbow. Here's why...
Kiriwina is fitted with a 1997 2GM20F. Last year I noticed SW leaking from the elbow.(Engine hrs around 1600)
The cause was a hairline crack in the elbow.
I had no trouble removing the elbow although the gasket did not come off cleanly. On close inspection I discovered that the inner tube was heavily pepper potted with traces of water.
After cleaning, pepper potting was clearly visible.
Had I not discovered this fault increasing amounts of water would have leaked back into the engine. A Yanmar tech told me this is a known problem.
At the time Yanmar in Argentina had no spares in stock. A local engineering shop rebuilt the elbow for me with a more robust inner tube and I made a replacement gasket.
No problems since.
Last edited by RBJ; 04-05-10 at 00:00.
Absolutely agree with the others that you should take it off to check. I'm about to replace mine. Maybe seems obvious but whether you refit the old one or a new one, you will need a new gasket.
2GM20 Exhuast Elbow Removal
Hi Guys thanks for all the replies and recommendations also the photos, thats settled then off it has to come.
Any idea how I can assist the removal of the bolts, as I said they are solid and I am just worried that I will shear them off?
2GM 20 Exhuast Elbow
Hi as previously said, I will take it off, and I tried to take this off today.
First problem I encountered is the bolts that hold the Elbow on are not 12mm and they are not 11mm either, or at least neither 11mm or 12mm won't fit, ones too small and ones too big.
So where do I go from here?
Do I cut the heads off and try to undo them with grips or something, or do I cound cut them off and try and use screw extractors? how successful are they?
Not sure now how to proceed for the best?