Flushing 2GM20 Raw Water Cooled

Daverw

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Just took out drain plug and found sand/mud that needs to be flushed out, not sure where to add clean water that will flush through block.
 

Spyro

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running the engine while up to temp is the same as flushing unless you mean putting something in and leaving there. Be careful flushing if the engine isn't running as there is a danger of getting water into the cylinders via the mixing elbow. You could run the engine when it's in the water and remove the drain. See what comes out. Or put the feed into a bucket and keep that topped up.
 

Daverw

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The boats out of the water, I was thinking of removing feed to mixing elbow and pushing hot water through engine and out of drain, was looking at using small electric pump to do this
 

pagoda

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The boats out of the water, I was thinking of removing feed to mixing elbow and pushing hot water through engine and out of drain, was looking at using small electric pump to do this

I had a raw water 3gm 30 previously. That was flushed out by drawing water from the pump inlet -via a hose from a large bucket with clean water. The bucket was suspended under the tansom at the exhaust - catching the warmer returned water. I used cheap white vinegar to circulate round - removing scale. I did remove the anodes prior to that and also soaked the thermostat in warm vinegar. It can get quite frothy in the bucket once it warms up! The water pump can pull from the bucket with no problem once primed.
 

black mercury

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The boats out of the water, I was thinking of removing feed to mixing elbow and pushing hot water through engine and out of drain, was looking at using small electric pump to do this
Do you have access to a hose connected to the mains? If so you could pump the water into the hose from the water pump going to engine. Some will bypass the engine and go straight to the exhaust elbow so you must have this disconnected. Water will flow into the block and out the drain plug, you could hold a finger over the pipe going to exhaust elbow to increase the pressure. Water will exit the drain plug and at the exhaust elbow. Quite common for deposits to gather around the drain plug, its at the lowest point. If you want to flush the whole engine you will need to remove the thermostat. Just make sure the water pipe is disconnected from the elbow before you start!
 

Major_Clanger

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This could be a good opportunity to de-scale the engine, and it's really easy to do.

Buy some Rydlyme, a brilliant de-scaler that actually works, and make a looped circuit.

Remove the pump impeller.
Bucket of Rydlyme mixed 50/50 with fresh water.
Electric pump in bucket feeding the water pump body.
Remove anodes but replace plugs.
Remove thermostat.
Remove exhaust hose and re-route back in to the bucket.
Run pump for a minimum of 2 hours (the design of the exhaust elbow should negate the possibility of water getting in to the cylinder).
Flush with fresh water.
Anodes back in.
Thermostat back in.
Impeller back in.
Presto!

The stuff will erode shells, barnies, scale and you may even see a drop in engine cooling temps once done.
 
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richardabeattie

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Surely it is not the big exhaust hose that you remove and reroute to the bucket but the water hose that goes into the elbow? And you don't mention the thermostat - surely that needs to be removed (and the cover replaced) to avoid all the Rydlyme going through the bypass?
 

Major_Clanger

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Surely it is not the big exhaust hose that you remove and reroute to the bucket but the water hose that goes into the elbow? And you don't mention the thermostat - surely that needs to be removed (and the cover replaced) to avoid all the Rydlyme going through the bypass?

Whoops, forgot about the thermostat, thanks. Better to have the de-scaler going through the last of the elbow so that as much as possible of the system is treated. It was exactly the exhaust elbow where the water jacket joins the exhaust that mine was blocked.
 

richardabeattie

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Sorry but not clear what "the last of the elbow" means. I think you mean take the water hose off the elbow and extend it back to the bucket to complete the circuit. But if you mean taking the main exhaust hose off the output side of the elbow then you'd need a large diameter hose to bring the outflow back to the bucket.
 

Daverw

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I nderstand that the main exhaust hose to be removed, I can do that as the water lock is next to the engine and could go into the bucket there and then run a 19mm to the water pump
 

richardabeattie

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Right, let's try and be clear. You mean leave the water connected to the elbow but disconnect the large diameter exhaust hose from the water lock and put it into a bucket. Then take a 19mm hose from that bucket to an electric pump feeding into the empty impeller housing. But why do you want to flush water on past the elbow and through the large exhaust hose? Surely sufficient to flush water and Rydlyme through the block as far as the water pipe feeding the elbow and from there to the bucket?
 

Major_Clanger

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Right, let's try and be clear. You mean leave the water connected to the elbow but disconnect the large diameter exhaust hose from the water lock and put it into a bucket. Then take a 19mm hose from that bucket to an electric pump feeding into the empty impeller housing. But why do you want to flush water on past the elbow and through the large exhaust hose? Surely sufficient to flush water and Rydlyme through the block as far as the water pipe feeding the elbow and from there to the bucket?

I've been perfectly clear. The object is to de-scale as much as possible of the engine's cooling circuit. That means returning the Rydlyme from the last possible place. Given the engine has a wet exhaust the return should be from the exhaust hose before it reaches the waterlock, if fitted. The principle is the same for any raw water cooled engine with minor alterations to suit type.
 
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