SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: BBF-ER on March 18, 2017, 09:12:22 AM
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Hello all, I picked up a 1976 Hallett bubble deck with a 455 olds and a berk jet awhile back. Its my first boat.
Had some minor work done on engine, mechanic said all is good. I haven't had time to take it out.
Runs fine at home with garden hose. I took it to pudding stone yesterday, got her butt in the water on the trailer and fired it up.
It got hot quick. I noticed that not much water was getting to water jets on exhaust and very little water from back water line.
Maybe i didn't have it deep enough? Don't know much about engines or jets.(newbie).Thanks.
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What kind of cooling system are you running? My 460 runs cold(160ish) on the water. Make sure you don't have any kinked lines. I'm no expert, but I think the water pressure from the hose is basically like going at speed on the lake.
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Thank for the reply,
I thought the cooling system on jets boats are the jet sucking water into jet bowl and pushing it out the jet and also through the engine block for cooling? When i had it at the lake and in the water it was pushing water through the jet fine, but not to the block.
I don't mean to question you. Like i said, Newbie. Thanks
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Make sure the gate valve is open. (Not all the way or you'll blow a head gasket)
Make sure the passage between the pump housing and the water hose to the block/exhaust isn't clogged.
I had seaweed in mine one time. Was getting hot fast.
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Thank for the reply,
I thought the cooling system on jets boats are the jet sucking water into jet bowl and pushing it out the jet and also through the engine block for cooling? When i had it at the lake and in the water it was pushing water through the jet fine, but not to the block.
I don't mean to question you. Like i said, Newbie. Thanks
It does. Steaveo's reply below yours is on track. Check to make sure the gate valve is open. It'll look like a spigot on the side of your house most likely, or it'll be a ball valve handle. Again, you want to make sure it's open and flowing through the block. Most of the time the hose fittings are on the upstream side of these valves so you won't notice it being closed on the hose. Having a pressure valve on the cooling port of your intake makes it handy for making sure you're not putting too much pressure into the cooling system.
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No blockage, checked intake and clean out port. I know water is getting to block when on hose.
I ran water hose on the hose from pump and it flowed through. I do have regulator that says 40-50 psi, is that right?
Im going to try it again on hose. Should i have gate valve closed when starting, then open when idling or a bit open all the time?
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On the lake I start with it just a little bit open (1 or 1.5 turns) then just idle around the lake and adjust it open or closed to achieve 180 degrees. Depending on who you talk to they may adjust a little warmer or cooler than that but 180 seems to be the average at idle. As far as the garden hose it depends on your water pressure. Mine is pretty high so I only have to turn my hose on about half way.
You typically don't want to go above 14-15 psi or you risk blowing through gaskets. That regulator might be stuck or bad. You can take it off completely and just use the gate valve.
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Open the gate valve all the way. Get the boat in the water, preferably at the dock, not on the trailer. Slowly close the valve until you see some temp on the gauge and with your hands...
Adjust it do you see no warmer than 150°F. should run cooler at speed....
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Olds I turn the gate valve to 21/2 open now one the hose u don't turn the hose wide open just let it trickle out the dump line. This is how I'm set up on the lake river ect. If u turn the hose up all the way u will milk the oil.
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Also gt jets knows his shit if not mistaken he tought me how to set up all the cooling system.
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My guess is that the regulator went bad.
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Thanks for the reply's, still working on it.
I think your right crazy jim, regulator is new but could be bad. Thats the only thing i can think of that would be blocking water flow.
Its one that is used on r.v's. I don't know if thats the right one. Im going to change it out. Thanks.
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Thanks for the reply's, still working on it.
I think your right crazy jim, regulator is new but could be bad. Thats the only thing i can think of that would be blocking water flow.
Its one that is used on r.v's. I don't know if thats the right one. Im going to change it out. Thanks.
Regulator?
Throw that crap in the trash.
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A couple problems that I see are:
It is really not a good idea to run the engine of a jet boat out of water without the drive line disconnected.
Radial clearance between wear ring and impeller (new) is .025 of an inch. A surprising amount of road grime finds its way into this gap. Running it on the trailer causes the wear ring and impeller to abrade, opening up this clearance, and degrading pump performance.
Another issue is the packings. The packings are actually lubricated leakage. Water pressure in the suction housing leaks past the packings, cooling and lubricating them. This is just not possible on a garden hose. If you are running the engine while on the launch ramp, you will need to need to have the pump deep enough in the water to completely submerge the impeller and pickings. This however presents another problem. The pump will suck debris off of the ramp, again abrading the impeller clearance.
Assuming you have a standard A cut impeller, there is only .125 of an inch clearance between the impeller shroud and the bowl. This presents a substantial restriction, between the impeller discharge and the cooling port in the suction housing. You need to have some decent pump flow (RPM) to provide adequate cooling.
GT Jets has a good recipe with a 3/4 pipe gate valve. Restriction increases as flow increases, providing sufficient cooling flow at idle while not blowing gaskets and freeze plugs at peak power. I think the best results will be tuning while underway.
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A couple problems that I see are:
It is really not a good idea to run the engine of a jet boat out of water without the drive line disconnected.
Radial clearance between wear ring and impeller (new) is .025 of an inch. A surprising amount of road grime finds its way into this gap. Running it on the trailer causes the wear ring and impeller to abrade, opening up this clearance, and degrading pump performance.
Another issue is the packings. The packings are actually lubricated leakage. Water pressure in the suction housing leaks past the packings, cooling and lubricating them. This is just not possible on a garden hose. If you are running the engine while on the launch ramp, you will need to need to have the pump deep enough in the water to completely submerge the impeller and pickings. This however presents another problem. The pump will suck debris off of the ramp, again abrading the impeller clearance.
Assuming you have a standard A cut impeller, there is only .125 of an inch clearance between the impeller shroud and the bowl. This presents a substantial restriction, between the impeller discharge and the cooling port in the suction housing. You need to have some decent pump flow (RPM) to provide adequate cooling.
GT Jets has a good recipe with a 3/4 pipe gate valve. Restriction increases as flow increases, providing sufficient cooling flow at idle while not blowing gaskets and freeze plugs at peak power. I think the best results will be tuning while underway.
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Thanks flusher and gt jets, I'm not far from pudding stone lake. Don't really want to disconnect drive line every time i want to fire it up.
Regulator is out and in the trash.What type regulator should i get and where can i pick it up? Thanks again.
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Thanks flusher and gt jets, I'm not far from pudding stone lake. Don't really want to disconnect drive line every time i want to fire it up.
Regulator is out and in the trash.What type regulator should i get and where can i pick it up? Thanks again.
A 3/4" Red and White gate valve and some hose bib adapters.....
Regulator is simply not necessary.
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You are somewhat eluding to having headers. Is that what you have? How large is the inside diameter of the dump fitting?
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Gt why not on the trailer
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Gt why not on the trailer
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The launch ramp is not deep enough. End of the dock. At least four feet of water.
That jet pump is one hell of a vacuum cleaner for the lake bottom. Deep clean water saves the pump from damage and prevents filling the block with sand/silt.
GT
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The launch ramp is not deep enough. End if the dock. At least four feet of water.
That jet pump is one hell of a vacuum cleaner for the lake bottom. Deep clean water saves the pump from damage and prevents filling the block with sand/silt.
GT
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I discovered this when I pulled my engine apart for the first time. It's amazing how much sand a 460 can hold in the water jackets. My garage looked like the beach. Havasu is a sandy lake.
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I discovered this when I pulled my engine apart for the first time. It's amazing how much sand a 460 can hold in the water jackets. My garage looked like the beach. Havasu is a sandy lake.
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Is that insane our what?
When I pulled the whitewater motor apart I was literally blown away. Full right to the gaskets.
GT
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