SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: firefly on March 22, 2007, 10:25:45 AM
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I just got my boat back from the shop the other day and i was running it at work here to see how it ran. I had the water hose hooked up so it had the cooling going on. My question is, when i started it it cranked right up and the temp gauge came up to about 100 after a mintue. It took another 2 minutes for it to go to 140. However, right after that it climbed rapidly up to the limit on the gauge of 240 in about a minute. Its a 460 with basset twisty headers. JP Marine tuned it up and readjusted the carb, when i picked it up Joe at JP Marine said she was running good.
Is this the normal operating temp? or is it climbing that fast because the jet is not taking in serious amounts of water like it would on a lake?
What temps do you guys run at?
One more question, when i had it running at idle at work i noticed when i looked into the nozzle of the jet that the impeller was not spinning. It was my impression that it would still turn even with the engine at idle. Or is it that it needs to be sucking in water for it to be spinning.
Sorry for all the rookie questions, im just trying to get the best understanding of how things work but i know the best learning platform is taking it out to the lake and actually doing it.
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240 is too way high. There's a couple of ways to hook the water up to it. You can hook the water hose up to a T that is sometimes there and sometimes not there. If it's there it would be near the valve coming out of the pump and going to the engine. The other way is to shove the hose into the pumps nozzle. The T will help save your engine and the hose up the nozzle will help save the pump. The only correct way to cool both is to put the boat in the water.
Another possiblity, and more likely, is that you may have an incorrect temp gauge sending unit.
You can't see the impellor through the nozzle. You were probably looking at the back internals of the bowl.
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I would say that you have one of two isses one is that your ball valve was only open a little bit.
the other is that the slide valve was not closed to the water you were pumping in was jusg going right back out
with out passing throught the engine.
I would look for a ball valve some where by the water neck on the engine and a faucet type valve by the rear
of the engine or by the pump.
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OH BOY!!! Sometimes admitting that your an idiot is your best defense! I took a look at where i hook up the hose and sure enough there was the valve i was supposed to open when i have the water flowing. What a rookie mistake! Ok, so with that said, i will run it again later and see what happens. Last night i only had it running for about 5 mintues if that, hopefuly it didnt do any damage.
I was also told that i should have the water valve for the headers open about 3/4 and leave it there, whether at idle or full speed. The valve is located at the front of the engine by the timing chain cover.
Hotrod,
I dont doubt you about looking through the nozzle and only seeing the internals. What i was looking at looked like the fan blades of a jet engine on a aircraft so i thought that was the impeller. What was i looking at then?
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Firefly, you were looking at the back (inside) of your bowl. The only way to see the impellor is from underneath the boat looking up into the inside of the pump.
Glad you found that valve!
Did Joe at JP tell you to leave that valve open? I could swear that Joe told my friend Mike to only have that valve open above 1500-2000 RPM. It's probably a different style of valve, or??
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If your boat is a jet do not ever do that again.
The engine will be fine without water but the pump needs it.
You will destroy the impeller very quick.
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I just ran the boat again, this time with the valve OPEN! The temp got up to about 190 after about 7 or 8 mintues but stayed there. From what i have been reading here its NOT a good idea to run the engine for any extended period of time out of the lake, for the engine sake as well as the pump because the garden hose just doesnt provide enough water. Is my take on this correct?
Emanon,
It is a jet and i will never do that again, i feel like a shmuck!
Hotrod,
Im pretty sure i heard correctly when Joe told me to leave it open 3/4 all the time due to the fact that the switch/valve is located by the engine and not accesible from the drivers seat. Joe had said that if the switch was located by the drivers seat as it is in some boats then to open it at the described RPM. He said it wasnt a big deal with my situation and that your not gonna destroy the headers because of the strength of Bassett headers. There just starting to blue so there still breaking in. I might be wrong but im pretty sure thats what he said when i picked it up. Anybody have any other input on this situation?
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Correct.
Yeah Mike's water valve is near his driver's seat. I was under the understanding that Mike shuts his valve at lower RPM's to avoid getting water back into his heads. I could be wrong though. I'd listen to Joe more than I would listen to myself. Hey, wait a minute... ???
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Man thats a great idea to put the valve by the seat I'm constiantly jumping to the back to close it.
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Man thats a great idea to put the valve by the seat I'm constiantly jumping to the back to close it.
Basset makes a presure valve so you don't have to do anything but drive. It shuts the water off at idle
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Yea, when i got mine serviced, JP Marine put a Bassett t-valve on there. Joe told me to leave the switch open at 3/4. The water does shut off at idle and comes back on at about 1500 rpm.