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Discussion Starter #1 (Edited)
Kinda stumped. Jet boat is overheating. Not getting alot of water pressure if any out of pump to engine. Pulled lines. Flushed everything out. Looked into pump housing outlet and it looks clean. Intake area looks clean as well. Back flushed everything. Still not getting water to the block. No water in oil either.
Before I pull the bowl. Is it possible to suck something in bowl that limits water to block but also allows jet to build pressure? I was able to still run up to speed but it wanted to overheating of course.
Btw. I'm running a Berk JC-A
 

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interesting

Can we assume you have a gate valve on the pump? If so did we check to see if it was fully open or better yet...does it function? Do you have a garden type hose end on the valve (to run water while on trailer) ? If so.......I would check the water flow/pressure while boat is in the water. Quick way to see by undoing the hose fitting from the gate valve, start her up and see if you have flow. Good to have a short piece of hose with a female end so you can direct hose overboard. 2 people much easier but totally do-able by yourself.:hmmm::hmmm:
 

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Pull the intake line that feeds the engine off the pump. blow a garden hose back thru the pump then to the engine. Keep an eye if anything blows out the pump, then back thru the engine and find the restriction. Most people have a problem warming up an engine in a pump boat. you have the reverse issue. FIND THE RESTRICTION into the engine and problem solved. MLAOP> M as an add on. if you are running logs remove the water intake to the logs and check the water flow thru the logs. Be careful not to fill the engine with water. M
 

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Discussion Starter #4
Yeah I did all that. That's the strange part. I backflused the entire system. No restrictions. I can flow garden hose water thru system. I also backflused thru jet, and it seems fine. After all that I took it back to ramp and still very little pressure out of pump??? But water is coming out of pump outlet to the block. I inspected gate valve and it's all good. I also removed line to pump and looked into hole which goes into the bowl and it looks clean.
I'm trying to figure out how I can have bowl pressure but no water pressure coming out of outlet to the block?
 

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Discussion Starter #6
Runnin logs...
Looks like I have a bigger issues.... pulled dipstick and I have water in oil....
Hopefully just a head gasket...
 

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Water in the block probably happened when you back flushed the motor,I always start the motor first then slowly turn the water on till a nice low stream comes out seen this happen more than once on motors.
 

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Discussion Starter #10
Water in the block probably happened when you back flushed the motor,I always start the motor first then slowly turn the water on till a nice low stream comes out seen this happen more than once on motors.
How is that possible? Are you thinking it flowed over the snails? It seems like it would dump out the back before that.
 

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How is that possible? Are you thinking it flowed over the snails? It seems like it would dump out the back before that.
Leadslinger is right. When running logs you cannot run water through it unless engine is running. Water will come in the open exhaust valves. Been there done that. Change oil & filter, run it to full operating temp, might have to change oil & filter again. Problem doing this now is you have another issue to resolve beforehand.
 

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Discussion Starter #12
yeah im not following ya? I dont see how water can get into the valves? The water from logs exits on the backside of the snails. Then dumps out the rear. Hows the water getting into the valves?
 

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Kinda stumped. Jet boat is overheating. Not getting alot of water pressure if any out of pump to engine. Pulled lines. Flushed everything out. Looked into pump housing outlet and it looks clean. Intake area looks clean as well. Back flushed everything. Still not getting water to the block. No water in oil either.
Before I pull the bowl. Is it possible to suck something in bowl that limits water to block but also allows jet to build pressure? I was able to still run up to speed but it wanted to overheating of course.
Btw. I'm running a Berk JC-A
Its likely that theres an issue in the jet itself which as you know is the "water pump" for the engine , a simple test would be to run the boat on a water hose if you find that it will not get hot under those circumstaces it will help proof out and diagnose your problem . Barring some oddity in your plumbing ..... didn't see which jet it was ?

* the water somewhat confusing reversion and ingestion problem into the engine mentioned by others is a problem separate from simple overheating that can occur from running on a hose when the water is turned on prior to engine start or other issues
 

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454..... Water is probably an 1/8th inch above.
kind of hard to visualize this. water should be at the bottom of the pan. water doesn't float on top of oil, oil floats on top of water. and it separates pretty quick. just change it and the oil filter and start all over again. most likely nothing wrong with engine unless it's packed full of sand. but I wouldn't run the engine very long with no water flowing out the exhaust because those neoprene exhaust hoses will start melting...

and to answer your first question, yes there could easily be something inside the bowl restricting flow that you aren't able to see without pulling the bowl off. been there done that...
 

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A friend of my Father's warmed his jetboat engine up in the driveway for an oil change......Shut the engine off and walked over to the faucet to turn water off......Changed oil, then went to start her back up.....>>Hydraulic lock<<...had to pull the sparkplugs and turn it over to get the water out of the cylinders...Can't remember if he had to do more damage control.....

I have a short additional hose with a gate valve on it for running the engine in the driveway.....Turn the water on ever-so-slightly (Just enough that the block fills up)......start it, and then quickly turn the water up to full.......BEFORE I shut down, I cut the water...Because the gate valve is right at the boat, I don't have to run around.

The low water pressure/overheating problem does sound like you have something clogging the water takeoff at the pump.....It may be a good idea to pull the bowl and impeller and have a look- a bit time consuming, but not too hard.....You do need a puller for the impeller, tho.....(I have one and am in the east bay....)
 

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Discussion Starter #16
If I go back and put boat in water how much water pressure should I see coming out of the pump if I disconnect it from the jet pump?
At idle?
Should I expect to see alot of water coming out at idle?
 

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pressure

Not sure about pressure as in PSI but it should be coming out of the tube pretty good! good flow at wide open gate valve at idle. Hope this helps.
 
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