Overheating Issue

[JOHN COOKSON]

I am a bit confused. When I remove the tstat I assume I should keep the bypass hose clamped off? Since I don't have a bypass valve should I partially clamp off the bypass hose? If I understand the water flow correctly, with the bypass clamped off won't the flush go to the engine by way of the water jacket? If that is the case then the acid won't have anywhere to go as indicated by the tests done thus far?(Yes) I'm going to try this. I just don't understand how the acid flush will pass through the blockage. I'll try almost anything to avoid removing the head.
Brian

I think you have it right. An acid FLUSH can't be an acid FLUSH until you have circulation through the engine. It will end up being more of an acid pickle. With out circulation through the engine the acid might not end up even getting to the clog.
Once again try removing the thermostat and clamping the bypass.

TRUE GRIT

[Marian Claire]

Bluewhale. Yes things have been confusing but I also think you have got it.
I would do this test:
1.T-stat removed,
2. Bypass hose clamped shut
3. T-stat housing off. ***
I would only use water for this test. No risk of splashing acid.This way you can actually see how much water, if any is going thru the block/head and the only way it can get to the "open housing" is thru the block. If you want to have the temp sensor removed that is fine and may be easier to see any flow depending on your access.

It will not take long to tell and will probable make a mess so be ready to shut her down. You may even have some water coming thru the bypass if the clamp is not perfect so be ready for that. I do not think you will damage anything down stream during this brief test.

The bottom line is we must have flow thru the block to cool the engine. Forget about everything else until flow thru the block is confirmed.
Dan S/V Marian Claire
Other questions/comments. I wonder if this test could be done with air? I believe BW does not have a valve in his bypass line because he has the double-action T-stat.

[BlueWhale]

Thanks for the clarification. It was too cold to try it today. It should be in the 50s this weekend. I'll keep you posted.

Brian

[Mo]

Where are you Brian? 7F here in Halifax today.

[Mo]

I am a bit confused. When I remove the tstat I assume I should keep the bypass hose clamped off? Since I don't have a bypass valve should I partially clamp off the bypass hose? If I understand the water flow correctly, with the bypass clamped off won't the flush go to the engine by way of the water jacket? If that is the case then the acid won't have anywhere to go as indicated by the tests done thus far? I'm going to try this. I just don't understand how the acid flush will pass through the blockage. I'll try almost anything to avoid removing the head.

It's suppose to get cold over the next couple of days but I think I'll endure it and give it a try.

Thanks.

Brian

Just clarify that you have water flow out the transom initially then it reduces and you get steam with reduced water flow...is that correct?

[BlueWhale]

Just clarify that you have water flow out the transom initially then it reduces and you get steam with reduced water flow...is that correct?

Yes, that is correct. Eventually it becomes all steam and no water.

[BlueWhale]

Where are you Brian? 7F here in Halifax today.

I'm in Baltimore, MD. Unfortunately, I didn't get to the boat as planned and will have to wait on this next cold spell to pass.

[Mo]

Yes, that is correct. Eventually it becomes all steam and no water.

Ok, if you initially have what appears to be normal batching just remove the T-stat and re-assemble the cover. Try it like that first. If that stops the steaming and rapid overheating there are a couple of things you can do to that would make your engine very dependable. I think that should be your first thing to do. When you get to the boat try that then text me @ nine oh two, four eight three, eight five two four. I know it can be a frustrating to make it to the boat, try a few things and "then what?...no fun heading back home to get a computer.


Also, if you have a cell phone or digital camera take some pics of your engine paying particular attention to the water hoses, pump area, T stat area, valves and exhaust etc. If you can get a video of the exhaust water output on start up and then stop the engine when it starts to steam that would help as well....but I think we will have this sorted out real soon so it might no be that pressing.

[joe_db]

It appears water goes around the engine but not through it.
If you run a water hose into the engine at one end (but not through the water pump itself) and close off the bypass, does water come out the other end?

[Ajax]

I might be crazy, but this sounds like a hose collapsing when it gets warm, or a t-stat failure.

[joe_db]

or...the block is plugged and as soon as it gets warm enough to open the thermostat the water flow can't go around anymore and stops. I had something similar happen to me once.

I might be crazy, but this sounds like a hose collapsing when it gets warm, or a t-stat failure.

[Mo]

Pic of block in my garage: I suggested the T stat removal and put in a by-valve when he started having issues...water pumping on start-up and then turning to decrease water and lots of steam. "my mechanic said"....anyway I just suggested. He changed the T-stat and overheated the engine first time he worked it hard. Comes back to me a couple of days later...I tell him again and he does it. Only now, engine hard to start, once started no steam, pumping fine but something is amiss...lots of blow by. I told him it has to come apart. Took a break down to see what happened and I told him he's NUMBER 3 that I know of that lost a block over a T-stat...and it was the T-stat.

So they get it apart and they rub some epoxy along the crack....holy sweet mother of ..... I just gave him an old block I had. I told him if he puts a T-stat in that block I gave him I'll take a round out of him. Rum delivery There was no need to loose that engine.

[BlueWhale]

Overheating Issue - Back at it!

Bluewhale. Yes things have been confusing but I also think you have got it.
I would do this test:
1.T-stat removed,
2. Bypass hose clamped shut
3. T-stat housing off. ***
I would only use water for this test. No risk of splashing acid.This way you can actually see how much water, if any is going thru the block/head and the only way it can get to the "open housing" is thru the block. If you want to have the temp sensor removed that is fine and may be easier to see any flow depending on your access.

It will not take long to tell and will probable make a mess so be ready to shut her down. You may even have some water coming thru the bypass if the clamp is not perfect so be ready for that. I do not think you will damage anything down stream during this brief test.

The bottom line is we must have flow thru the block to cool the engine. Forget about everything else until flow thru the block is confirmed.
Dan S/V Marian Claire
Other questions/comments. I wonder if this test could be done with air? I believe BW does not have a valve in his bypass line because he has the double-action T-stat.

Ok. Seems like spring has sprung and I need to get on the water. I removed the t-stat and attached a hose to the back of the t-stat hosing. The water flow was very good! Initially, it was black but cleared up after a short while. So, does this in fact indicate that water IS flowing through the block? I am assuming that removing the t-stat replicates the state the t-stat is in when the engine temp rises to 180+?

I attempted to remove the elbow at the end of the engine but it's going to take some work to remove it. In the meantime I will replace the hose that connects to the exhaust pipe. It feels a bit weak. Perhaps it is collapsing as the engine heats up. I'm headed to the store for the hose while the PB Blaster works on the elbow. Wish me luck 😄.

Brian
Rekofa the Blue Whale
1979 C&C34

[JOHN COOKSON]

(1) So, does this in fact indicate that water IS flowing through the block? (2)I am assuming that removing the t-stat replicates the state the t-stat is in when the engine temp rises to 180+?
1979 C&C34

(1) Don't go by "indications" and suppositions. Some water may be going through the engine, but how much? Camp the bypass hose. Or if you have a valve in the bypass hose close it. This will force all the cooling water through the engine. If you don't have a valve on the bypass and clamping the bypass makes the engine run at a normal temp then put a valve in the bypass so you can balance the flow around the engine with the bypass vs the flow through the engine with the valve. Once you have established flow through the engine it would be a good time to do an acid flush, especially since you reporter you blew a lot of KRAP out of the cooling system. There is one way to tell for certain that whether or not you are getting enough water flow through the engine. Run the engine until the thermostat is open. Clamp the bypass. Remove the hose at the hot section and direct the water output from the manifold to the bilge or cockpit. Start the engine and rev it up a bit. Output should be like a garden hose.* Just do this briefly because without cooling water you can damage hoses and plastic mufflers.
*However some water passages may be more blocked than others resulting in uneven cooling. Most likely true in all RWC engines.
(2)No, not really. It would of course only be somewhat true if the thermostat was working properly. Even a properly functioning thermostat will somewhat restrict the flow through the engine just because it is in the way of the flow. It will act as a partial restriction. As previously suggested why not remove the thermostat, for now as least, and get rid of a variable. I'll bet you $0.10 with a valve on the bypass and no thermostat you will be happy.

TRUE GRIT

[BlueWhale]

Overheating Issue - Back at it

Thanks for the reply True Grit. The by-pass was clamped off. The water flow was steady. I worked my way all the way back to the wet exhaust hose. The water flow was adequate and steady at each stage. I replaced the wet exhaust hose but it now appears that my coil has gone bad. I was planning on switching over to an electronic ignition. It seems like now is the time. I installed the new hose and reinserted the thermostat to see if in fact the issue was the hose. I can't check it until I address the ignition issue. I'm ordering the upgrade kit today - or at least a new coil . I'll be back.

Brian

Rekofa the Blue Whale
1979 C&C34