Engine/exhaust elbow flush?

[stephen_h]

Hi,

My Yanmar 3GM30 ( raw water cooled) has been overheating.

I have changed impellor and thermostat and water is exiting the exhaust outlet.

I am going to pump some Rydlyme around the engine to clear it out.
I am thinking of pumping into the engine after the water pump and then out through the exhuast elbow so that gets flushed as well.

Is this okay. Don't want to pump water where it's not supposed to go !

 

[scottie]

Perhaps taking care that you not flood the exhaust system which needs a running engine to clear the water out the system
It may be the start of a blocked exhaust elbows!

 

[stephen_h]

Perhaps taking care that you not flood the exhaust system which needs a running engine to clear the water out the system
It may be the start of a blocked exhaust elbows!

That was what I am not sure about, flooding the exhaust/engine so maybe not such a good idea.

I do suspect the elbow but the bolts holding it on are very corroded and with sailing imminent I didn't want to try to remove it and end up with an even bigger problem.

 

[Tranona]

I don't think flushing in that way would have any impact on deposits in the elbow. Unlike the water passages it does not fill with water. The flow is only a spray into the exhaust flow. The only way to clean it is to remove and physically clean or immerse in a cleaner like brick cleaner.

 

[scottie]

If you can remove the exhaust pipe and catch the flow that be an alternative but it is not always the best introduction to wrestling in the bilges

 

[stephen_h]

I think the bidge wrestling will be better than rounded off bolt heads but Tranona suggests it won't have much effect on any build up.

 

[scottie]

I think the bidge wrestling will be better than rounded of bolt heads but Tranona suggests it won't have much effect on any build up.

He is blunter than me but I would say he is suggesting the same thing

 

[geem]

If you have cast iron elbow, in my experience you need to remove it and remove the carbon. This is best done with a Dremel. Flushing will have zero effect.

 

[PetiteFleur]

When my exhaust elbow blocked up - a Perkins Perama 20 - I removed the cast iron elbow, it only had a 10mm hole for the exhaust, took it home and my screwdriver went straight through the casting! Replaced with the Volvo Penta equivalent which was cheaper than Perkins...

 

[geem]

When my exhaust elbow blocked up - a Perkins Perama 20 - I removed the cast iron elbow, it only had a 10mm hole for the exhaust, took it home and my screwdriver went straight through the casting! Replaced with the Volvo Penta equivalent which was cheaper than Perkins...

All the cast elbows have a shorter life than stainless. I convertered my cast elbow on the generator to s/s and it no longer blocks up. I used to routinely decoke the elbow every 100 hours. I only do it now every 500 hours

 

[nevis768]

That was what I am not sure about, flooding the exhaust/engine so maybe not such a good idea.

I do suspect the elbow but the bolts holding it on are very corroded and with sailing imminent I didn't want to try to remove it and end up with an even bigger problem.

It's probably the best solution to remove it, you might be lucky and get the bolts without too much trouble. You can always try to get them off and stop without causing any damage.

 

[vyv_cox]

That was what I am not sure about, flooding the exhaust/engine so maybe not such a good idea.

I do suspect the elbow but the bolts holding it on are very corroded and with sailing imminent I didn't want to try to remove it and end up with an even bigger problem.

Removing corroded bolts in the boatyard will always be preferable to doing it at sea. Bite the bullet and sort it now, saving possible massive problems in future.

 

[stephen_h]

I have now run Rydlyme through the engine for a few hours and after running at the berth = in forward - for about 20 mins it seemed to reach a temperture of 42 C which is about right acording to the manual. Hopefully that was the overheating problem.

Still want to check the elbow and was wondering if I removed the manifold and elbow together could I then flush/soak both in brick cleaner?
Also better option to remove elbow bolts.

 

[wingcommander]

You know your gonna eventually have to remove those exhaust elbow bolts, as Vyv says do it sooner as opposed later.
I was surprised to see how restricted my Bukh elbow was and yes it took a good soaking and poking to get it usable again.