OVERHEATED

« **Reply #25 on:** July 10, 2016, 08:48:51 PM »

The relief valve is between the jet and the gate valve? If so, it is bypassing all the flow before it has a chance to get to the engine, which is just getting a trickle of flow.

Don't run it on the trailer, you are going to burn up that new pump!

« **Reply #26 on:** July 10, 2016, 09:26:03 PM »

Quote from: Flusher on July 10, 2016, 08:48:51 PM

The relief valve is between the jet and the gate valve? If so, it is bypassing all the flow before it has a chance to get to the engine, which is just getting a trickle of flow.

Don't run it on the trailer, you are going to burn up that new pump!

Flusher,

Hey bud.
Pressure relief valve is gone, just a gate valve now.
Now way I'm gonna run it on the hose with the $$$ pump connected. I'll pull the driveline for that.
What I was doing today was more of a manual flush, to see if there were any blockages, or major restrictions in the cooling system from the engine side of the gate valve on up & thru the gate valve back out through the pump….
Now that i got you here, what do you think about the possibility that the pump might not be providing enough pressure or volume of water to adequately circulate water through the engine? Impossible?
No disrespect brother, just expressing my cluelessness.

« **Reply #27 on:** July 10, 2016, 10:06:50 PM »

O.K.,
More wild guessing: water volume vs. water pressure

So, before putting the boat on the water, while the pump was out being rebuilt, I did a baseline tune running the engine on the garden hose. Had a water pressure regulator with gauge, on the hose set to 15 psi. Ran the engine for upwards of 10 minutes, & it stayed cool the whole time. was able to regulate the water temp between 120 & 140 degrees just by turning the spigot open or closed just a little bit. The WPR gauge reads zero the whole time, which indicates that the same amount of water going in is going out, right? The regulator limits the pressure but not the volume, so I have 15 psi., max, with a decent volume of water going to the engine, & everything is peachy. Get it back on the water, setup is the exact same only now the new pump is providing water to the engine.
Could it be that, lets say, the water passages in the block, heads or the exhaust manifolds are restricted or crudded up enough that they would pass enough water to keep the engine cool when fed by residential water line volume, but not with the kind of volume that you would get from a pump under normal operating conditions, even if, lets say, the pressure provided in either situation is around 15 psi.?

« **Reply #28 on:** July 11, 2016, 09:33:57 AM »

Just a question-

You said the gauge went over 220, But was the engine hot?
Just thinking about a mismatched Temp gauge and sender.

Dan'l

« **Reply #29 on:** July 11, 2016, 11:44:21 AM »

Quote from: mash on it on July 11, 2016, 09:33:57 AM

Just a question-

You said the gauge went over 220, But was the engine hot?
Just thinking about a mismatched Temp gauge and sender.

Dan'l

Had that happen before, first time we took the Hankey boat out with the blower motor. Gauge pegged 250 thought motor was done. But happen to just be mismatch sender.

BECKY WITH THE GOOD HAIR!

« **Reply #30 on:** July 11, 2016, 11:55:31 AM »

Good call, FWIW, you can't touch over about 190°F without evacuating a swear word. 150°F you can set your hand on for several seconds.

GT

« **Reply #31 on:** July 11, 2016, 12:02:50 PM »

Quote from: mash on it on July 11, 2016, 09:33:57 AM

Just a question-

You said the gauge went over 220, But was the engine hot?
Just thinking about a mismatched Temp gauge and sender.

Dan'l

Definitely hot.
First time it happened a couple of weeks ago, after shutdown, I could hear water water steaming & boiling in the block. Temp gauge was pegged at 240.
Yesterday, not so much, but got it shut down by the time it hit 220........

« **Reply #32 on:** July 11, 2016, 12:16:34 PM »

Pressure is result of resistance to flow. In order for flow to occur, there must be a pressure differential and a flow path. There is no way that just the pump being submerged could cause any flow to occur.

On your boat (sitting level), the water pump mount on your block is about 10" above the cooling line fitting in the jet pump and the thermostat housing flange on the intake manifold is about 17" above the cooling line fitting. Because the weight is aft, the stern will sit lower in the water than the bow, increasing these numbers. The block won't even fill with water until you start the engine.

If you are observing flow through the engine while under way, that has to be produced by the jet pump. I just can't see that the jet pump isn't producing enough flow to cool the engine yet produce enough flow to generate bowl pressure, and thrust, with the water exiting a 3.125" nozzle opening.

Barring the possibility of a ski rope or something getting sucked up, winding around the back side of the impeller, and creating a seal between the back side of the impeller and the suction housing; the the restriction has to be between the jet pump cooling line fitting and where the water returns to the lake. I believe you wrote that you tested flow in both directions.

I would lose the pressure relief valve. I would verify that your gate valve is opening/closing all the way as it should be. Start with it all the way open and adjust down from there.

I also think Dan'l is spot on with what he just said. I would add, make sure that the sending unit is getting a good ground.

Lastly, I would check your tune. Tuning on the trailer is much different than with the engine under full-load. You might be leaning out. I will share this little tidbit; my engine leaned out, while cruising, as a result of a hose failure on the main fuel line between my fuel pump and barrel valve. The engine got so hot that I could feel the heat radiating on my back at about 50 MPH. It felt like the back of my neck was getting sunburned, but the sun was in front of me. I run full pump pressure through my engine, which renders my water temperature gauge useless, because it never registers any temp unless I am idling for long periods of time. The surface of the heads got hot enough to blister my finger when my dumb @$$ touched it.

« **Reply #33 on:** July 11, 2016, 01:07:31 PM »

Quote from: Flusher on July 11, 2016, 12:16:34 PM

Pressure is result of resistance to flow. In order for flow to occur, there must be a pressure differential and a flow path. There is no way that just the pump being submerged could cause any flow to occur.

On your boat (sitting level), the water pump mount on your block is about 10" above the cooling line fitting in the jet pump and the thermostat housing flange on the intake manifold is about 17" above the cooling line fitting. Because the weight is aft, the stern will sit lower in the water than the bow, increasing these numbers. The block won't even fill with water until you start the engine.

If you are observing flow through the engine while under way, that has to be produced by the jet pump. I just can't see that the jet pump isn't producing enough flow to cool the engine yet produce enough flow to generate bowl pressure, and thrust, with the water exiting a 3.125" nozzle opening.

Barring the possibility of a ski rope or something getting sucked up, winding around the back side of the impeller, and creating a seal between the back side of the impeller and the suction housing; the the restriction has to be between the jet pump cooling line fitting and where the water returns to the lake. I believe you wrote that you tested flow in both directions.

I would lose the pressure relief valve. I would verify that your gate valve is opening/closing all the way as it should be. Start with it all the way open and adjust down from there.

I also think Dan'l is spot on with what he just said. I would add, make sure that the sending unit is getting a good ground.

Lastly, I would check your tune. Tuning on the trailer is much different than with the engine under full-load. You might be leaning out. I will share this little tidbit; my engine leaned out, while cruising, as a result of a hose failure on the main fuel line between my fuel pump and barrel valve. The engine got so hot that I could feel the heat radiating on my back at about 50 MPH. It felt like the back of my neck was getting sunburned, but the sun was in front of me. I run full pump pressure through my engine, which renders my water temperature gauge useless, because it never registers any temp unless I am idling for long periods of time. The surface of the heads got hot enough to blister my finger when my dumb @$$ touched it.

Flusher,

Thanks for the detailed response!

Yesterday, I ran her with just the gate valve. (Removed the PRV & re-plumbed before getting on the lake.) Gate valve was 100% open.
Didn't get above 1200 rpm's, basically idling and the temp kept climbing. I believe it would have passed 220 if I hadn't shut it down.
I like the leaned out theory, & wish it was that, but I didn't really get much past the idle circuit while it was running. If it was that leaned out, I don't think it would even idle?

It's looking more like, as you said, a restriction of some kind on the engine side of the jet pump cooling line fitting.....

« **Reply #34 on:** July 11, 2016, 01:36:30 PM »

Quote from: garytcosta on July 11, 2016, 01:07:31 PM

It's looking more like, as you said, a restriction of some kind on the engine side of the jet pump cooling line fitting.....

Including the fitting! It isn't somehow restricted, is it?

What about timing? It's not crazy retarded, is it?

I don't remember what it is, but something struck me as weird on your boat. Is your water plumbed through the exhaust before entering the engine? I was not involved in the work and whatever it was was not something that we were involved with. I'm trying to learn to STFU because every time I say something, it opens a can of worms.

Only other thing I got is engine clearances. Pull the spark plugs and turn the engine over with a breaker bar, feeling how much torque it takes to turn it. If the clearance is too tight, you should be able to feel it.

« **Reply #35 on:** July 11, 2016, 03:32:03 PM »

Fwiw.. I had a timing issue with my street car once after a distributor swap, car ran and drove fine but started overheating really bad,something it never did before, after it cooled down I fired it a night to check it out and the headers were glowing red! Turned out the distributor was f'd up and way retarted, locked it out at 36 degrees and problem solved...

« **Reply #36 on:** July 11, 2016, 04:23:14 PM »

Quote from: aquaholic72 on July 11, 2016, 03:32:03 PM

Fwiw.. I had a timing issue with my street car once after a distributor swap, car ran and drove fine but started overheating really bad,something it never did before, after it cooled down I fired it a night to check it out and the headers were glowing red! Turned out the distributor was f'd up and way retarted, locked it out at 36 degrees and problem solved...

I wish it was as simple as timing being too retarded
Timing is at 13° btdc initial, 34° all in.
I'm reserving the retarded part for myself.

Flusher

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