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View Full Version : major over heating issue ,please advise i'm stumped



POUNDERS
05-04-2013, 07:49 PM
ok guys,hears the deal,i plumbed my jet boat last weekend, and yes its right lol...so i have my boat out for over three hours ,all types of driving from wot to just putting around looking at house boats.it NEVER got over 150-160 degrees all day,,as im going back to the dock my boat instantly started spiking to 250 deg and sputtering like hell,,,yes i'm over heating at this point...but why the sudden spike and it diddnt cool down till she was shut off.i looked in the clean out and felt around,diddnt feel or see anything.what gives..i did go over a few big wakes right before it spikes[ any relation ].brand new olds 455 with over transom wet headers and like i said it ran like a champ all day ,well till last 10 minutes lol..what do i look for that might be clogged,my headers run off one side of my thermostat delete housing and the other is plumbed to over flow. any ideas would help as to why it just spiked and stayed there would help:41616-4:

T8er S.
05-04-2013, 08:34 PM
ok guys,hears the deal,i plumbed my jet boat last weekend, and yes its right lol...so i have my boat out for over three hours ,all types of driving from wot to just putting around looking at house boats.it NEVER got over 150-160 degrees all day,,as im going back to the dock my boat instantly started spiking to 250 deg and sputtering like hell,,,yes i'm over heating at this point...but why the sudden spike and it diddnt cool down till she was shut off.i looked in the clean out and felt around,diddnt feel or see anything.what gives..i did go over a few big wakes right before it spikes[ any relation ].brand new olds 455 with over transom wet headers and like i said it ran like a champ all day ,well till last 10 minutes lol..what do i look for that might be clogged,my headers run off one side of my thermostat delete housing and the other is plumbed to over flow. any ideas would help as to why it just spiked and stayed there would help:41616-4:

Just throwing out ideas, check the jet intake, line coming off pump, any valves that adjust water pressure for any debris. Could some valves have closed when you hit the wakes? Line come off. :4_6_2v:

POUNDERS
05-04-2013, 08:53 PM
to check the jet intake do i just crawl under boat and look around lol?i looked for hoses that may have blown or come off[ nothing there ]i have two valves,one in back from pump which i keep wide open,havnt checked that,and the other is to adjust water flow on headers,i'll check that to.is there common shit i need to look at cleaning on these set ups,and beyond just feeling in the clean out is there anything else i'm supposed to do...i'm trying to learn everything i can about jet boats now,my last boat was maintained by a boat tech in missouri and now its all me in cali lol.

T8er S.
05-04-2013, 09:07 PM
to check the jet intake do i just crawl under boat and look around lol?i looked for hoses that may have blown or come off[ nothing there ]i have two valves,one in back from pump which i keep wide open,havnt checked that,and the other is to adjust water flow on headers,i'll check that to.is there common shit i need to look at cleaning on these set ups,and beyond just feeling in the clean out is there anything else i'm supposed to do...i'm trying to learn everything i can about jet boats now,my last boat was maintained by a boat tech in missouri and now its all me in cali lol.

Yeah just crawl under to check the intake, defiantly check the valve in the back. Here's my thought process, water in through pump/check that all is clear, valve off pump/ check that it's open and clear, lines going into motor/check that they are clear. Once you've checked all that check all other water lines and valves. If you don't find anything maybe something was up against your intake blocking it and when you shut off the boat it dislodged. So if you don't find anything maybe back her in the water and let her run on the trailer and see what happens. (The smart guys are like vampires they should be checking in soon to line me out) :23_6_118:

POUNDERS
05-04-2013, 09:50 PM
someone told me i could flush block,and pump...is this b.s or is it true..i havnt started boat in shallow water so having a new motor i dont think motor flush is needed,but pump..hmmm..i did remove thermostat delete and look in manifold for what thats worth lol..i'm bummed lol it ran like a champ all day till last quarter mile where all the ladies were lol.

T8er S.
05-04-2013, 09:58 PM
someone told me i could flush block,and pump...is this b.s or is it true..i havnt started boat in shallow water so having a new motor i dont think motor flush is needed,but pump..hmmm..i did remove thermostat delete and look in manifold for what thats worth lol..i'm bummed lol it ran like a champ all day till last quarter mile where all the ladies were lol.

Haha every time, I'm sure you can flush them just don't ask me how. :spit:

POUNDERS
05-04-2013, 10:06 PM
i appreciate the input,,i will definitely figure it out.i want to make it to cfw soon ,i was at lime saddle today and plan on being at a lot of vjb outings this year.i was impressed at how well this tahiti handled though.big wakes or not it was super solid and turns on a dime.my last jet boat was a 77 massi custom 19 ft 454 and was not as forgiving in choppy water.

David
05-05-2013, 08:18 AM
Sounds to me like you got a piece of debris into your water lines... I think I'd pull my water lines and clean out...
Maybe hook the hose up and see how the waters flowing on the trailer...
Open and close the valve a couple times while the water is running in case something is lodged there...? :zz2cents:

wolfie
05-05-2013, 10:36 AM
Sounds to me like you got a piece of debris into your water lines... I think I'd pull my water lines and clean out...
Maybe hook the hose up and see how the waters flowing on the trailer...
Open and close the valve a couple times while the water is running in case something is lodged there...? :zz2cents:

Like David said, you may have something in the intake or line. Are you running a T-state?
You can flush your block if you want. You just can't run too much pressure through it and you also need to make sure that you shut off the water to the headers.

POUNDERS
05-05-2013, 12:33 PM
No I don't run a thermostat just strait flow.so should I take off the intake manifold and check there?I will check all water lines as well.I am def gunnu change oil as well.

wolfie
05-05-2013, 12:39 PM
No I don't run a thermostat just strait flow.so should I take off the intake manifold and check there?I will check all water lines as well.I am def gunnu change oil as well.

I wouldn't take the intake manifold off. I was talking about the suction intake on the pump. If your problem means taking off parts, it would be the heads for a blown head gasket. Did you check the oil for water?
I think maybe there was something in the suction housing intake or the feed lines.

POUNDERS
05-05-2013, 01:06 PM
to be honest,i have the basic knowledge of how a pump works but have never looked at one to carefully.is the suction pump visible from bottom grate.as far as the oil i havnt checked it,affraid to ,i had to run her hot for 10 miutes to get out of main lake to dock,so head gaskets may be blown now but were not the cause i dont believe.she ran hot enough to not stay running ,but after she cooled down fired right up [ you could say it was the worst time and place on the lake to act up ] wake boarders killing me with swells.as far as the suction on the intake side of pump any suggestions on quick way to check or how

White Lightning
05-05-2013, 01:23 PM
to be honest,i have the basic knowledge of how a pump works but have never looked at one to carefully.is the suction pump visible from bottom grate.as far as the oil i havnt checked it,affraid to ,i had to run her hot for 10 miutes to get out of main lake to dock,so head gaskets may be blown now but were not the cause i dont believe.she ran hot enough to not stay running ,but after she cooled down fired right up [ you could say it was the worst time and place on the lake to act up ] wake boarders killing me with swells.as far as the suction on the intake side of pump any suggestions on quick way to check or how

Just look everything over as closely as you can and then start taking off cooling lines and flushing them backwards . As far as the engine goes, I always run the bolt in neoprene freeze plugs in the lowest freeze plug hole on the block. Draining the block and flushing it is "so easy a cave man can do it" lol.
Rob

POUNDERS
05-05-2013, 01:35 PM
i tend to forget that i'm dealing with a common big block motor because it sets in my jet boat lmao, i think a lot of people do...this week i will take all advise given and perform hose check and pump check.change plugs,oil,and grease pump.i will check all valves as well,i'll update when performed and what i find or dont find lol.motor only has 10 hours on it so hopefully i diddnt scatter the damn thing

wolfie
05-05-2013, 08:02 PM
i tend to forget that i'm dealing with a common big block motor because it sets in my jet boat lmao, i think a lot of people do...this week i will take all advise given and perform hose check and pump check.change plugs,oil,and grease pump.i will check all valves as well,i'll update when performed and what i find or dont find lol.motor only has 10 hours on it so hopefully i diddnt scatter the damn thing

There's a cleanout on top that you can take off and feel around inside if you don't want to crawl underneath.

POUNDERS
05-14-2013, 09:56 PM
Ok,I went through all of my plumbing and nothing but smooth flow.block flushed,hoses checked,pump checked etc.I did however notice a few other things.remember its a olds 455 hei.plugs were gapped at.70,I know they can go as high as .80 but what a large gap.what's a good plug and gap for stock 455 w/ hei.anyways my new edle 650 would not adjust off left side set screw.my buddy thinks when I hit a wake it might have either bent or stuck a butterfly and ran it hot on a fuel mix..is this really possible.and another thing he said was we are not supposed to Cruz at same rpm for periods at a time.don't remember why...hmmm..oil was clean no milk shake.havnt went through carb to verify anything yet but that's the point I'm at

newtojets
05-14-2013, 10:07 PM
do you have a water pressure gauge ??? sorry im new to this thread.

newtojets
05-14-2013, 10:08 PM
if the water spiked something got stuck in there have you had it back in the water since??? to test.

"THE ADVOCATE"
05-14-2013, 10:14 PM
Head gasket? Not enough to mix oil but restrict water?

78_Tahiti
05-15-2013, 04:42 AM
The Edelbrock Carb is very easy to work on. But there are a couple of things that will make it simpler. before taking the top off the carb (on edelbrocks) first loosen the screw on both of the metering rod cover plates, the slide the little covers open, and remove the metering rods, and springs. this makes it way easier to reinstall the top of the carb as well, after you peak inside.

White Lightning
05-15-2013, 12:01 PM
The Edelbrock Carb is very easy to work on. But there are a couple of things that will make it simpler. before taking the top off the carb (on edelbrocks) first loosen the screw on both of the metering rod cover plates, the slide the little covers open, and remove the metering rods, and springs. this makes it way easier to reinstall the top of the carb as well, after you peak inside.

Personally I'm not a big fan of the Eddelbrock/AFB style carbs. They have a tendency to have an off idle lean condition that can run you ragged trying to get the air bleeds regulated. That carb design was introduced back in the 50's and hasn't been improved on much since. I'm running one on my bus/motor home BBC and, even though it's new, it doesn't run/idle well at all. I've got a Q-jet replacement Holley spread bore coming for it.....BUT, like you say, they ARE easy to work on.


Pounders, if one of the idle mixture screws was non responsive to adjustment, that means that it either has a clogged/restricted passage in the carb or there is a vacuume leak some where in the runners that that side of the carb supplies. A stuck throttle plate will give you a high idle or a carb that won't open.
Rob

H20MOFO
05-15-2013, 12:32 PM
ok guys,hears the deal,i plumbed my jet boat last weekend, and yes its right lol...so i have my boat out for over three hours ,all types of driving from wot to just putting around looking at house boats.it NEVER got over 150-160 degrees all day,,as im going back to the dock my boat instantly started spiking to 250 deg and sputtering like hell,,,yes i'm over heating at this point...but why the sudden spike and it diddnt cool down till she was shut off.i looked in the clean out and felt around,diddnt feel or see anything.what gives..i did go over a few big wakes right before it spikes[ any relation ].brand new olds 455 with over transom wet headers and like i said it ran like a champ all day ,well till last 10 minutes lol..what do i look for that might be clogged,my headers run off one side of my thermostat delete housing and the other is plumbed to over flow. any ideas would help as to why it just spiked and stayed there would help:41616-4:

You say its plumbed "right".....there are a lot of ways to skin that cat. You say your headers are plumbed out of the thermostat housing....are you running a bassett t valve?? Are you sure the valve is adjusted/operating? Do you have a gate valve on the supply line off the jet? Is there a gate valve on the dump line?....some people do that to adjust the rpm at which the headers get wet? Are these valve(s) wide open? Jets will always run hotter at idle because there is less water pressure then....but if all is ok...it shouldn't over heat. Did you pull a block drain plug to inspect for sand in your block.....of to see if your block has been filled or partially filled?? I like to be able to see my dump line/water....so I KNOW I have good flow. Good luck.

POUNDERS
05-16-2013, 06:34 PM
check,check and check...the funny thing is ,i can idle my jet boat all day and wont over heat,i idled for a hour in a no wake zone looking at house boats and never crested 165-170..like i said it happened instantly not a gradual heat up.i do remember hitting a big wake around that moment of over heat,with that being said i wonder if the two are related.as far as my plumbing alot of the top guys have looked at my plumbing diagram and with all of their mutual agreement on mods i should and did make she ran like a champ.i fired it up yesterday and idled perfect held at good temp readings,when i cracked the throttle it fell on its face,sucked a carb gasket?bent butterfly-float?carb wont adjust of secondaries now..edle 650.i run two fuel filters and both changed as well.is there a filter i can run for my water to block?

FIRECAPT1957
05-24-2013, 07:18 PM
Pounders , If you have a gate valve on pump inlet ,make sure the gate didnt break off from the stem or was broken before & the big wakes jarred it loose & its not letting water thru or highly restricted flow , sounds far fetched ,but really its not

John ( Firecapt 1957 )

White Lightning
05-25-2013, 09:43 AM
Yeah, it definately sounds like a flow problem to me.......
Rob

stroker
06-17-2013, 09:26 PM
No I don't run a thermostat just strait flow.so should I take off the intake manifold and check there?I will check all water lines as well.I am def gunnu change oil as well.

don/t just look at intakes but also look at your dump sources. Restricted dumps can also be a source of overheating as you are not dumping water fast enough. Your dumps should have a greater combined cross sectional area than your intake. I am experiencing a similar problem after I stroked my sbc 400 to a 434. Too much restriction on the dump side of the stat housing through AN fittings and both lines merging to one at another AN tee fitting. Changing to two 5/8 dump hoses going into individual thru hull fittings at the transom.

stroker
06-17-2013, 09:30 PM
You can get a sea water strainer and hook in after your valves on the intake side. You can get one at any marine supply outlet.

Lasttoy
06-19-2013, 11:46 AM
You must have a thermostat, even if you take the guts out of it to restrict the speed of the water flowing thru the motor.. i take the spring and all out of mine.
you must not have more than 25 psi in the motor.. i recommend installing a pressure relief valve with overboard dump line, anymore than 24psi will blow head gaskets..
if you plumbed it for a jet boat then you can hook a hose to it in yard and check all of these.. i install water pressure gauges in my intake. and water temp gauge directly on motor to ensure it is correct. .i also use a OIL time gauge ..
i have put regular thermostats for 180 in the motors.. but you have to have something to slow the water flow or your motor will over heat..