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Discussion Starter #1
ok guys I got one for yall,
I got a 1973 Wriedt with a 460 BB in it, and i was runing wide open accross the lake bout 7am when the water was like glass, and then all of a sudden the engine ran hot and shut down on me, it wouldnt even turn over so i let it set for bout 45 minutes to let it air cool then hooked my bilge pump to it and run water through the engine to get it cool, fired it up drove it back to dock, brought it home and did a compression check one side of engine (all 4 cylinders) is runing 125 lbs of compression, the other side 1 cylinder 75 lbs other 3 cylinders 55 lbs, no water in oil and spark plugs are clean (no oil on them) so is it a head problem? or a cylinder problem? if it was a cylinder wouldnt my plugs have oil on them? and if it was a head problem wouldnt I have water in my oil?

any help would be greatfull
 

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I would be willing to bet you have a blown head gasket in the low head, also, did you have the throttle butterflies 100% open when you did the test?. Could be giving you some bad #'s otherwise.

Good luck!

GT :)hand
 

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Discussion Starter #4 (Edited)
forgot to mention that there's some blow by on the vent in the valve covers....blown head gasket would be great, i was thinking the worse....... no i didnt hav the butterflies open whe i did it but i"ll try it..........thanks

will it hurt to finish out the summer like it is or does it need replaced asap????????????
 

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A.S.A.P. or sooner. Period. With 4 weak cylinders on one side theres something major going on. You`ll be lucky if its just a head gasket.
 

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Discussion Starter #6
what do you think it is, richard?
 

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ok guys I got one for yall,
I got a 1973 Wriedt with a 460 BB in it, and i was runing wide open accross the lake bout 7am when the water was like glass, and then all of a sudden the engine ran hot and shut down on me,

While it's apart check the pin in the dizzy to make sure it's not sheared or at least started to shear. When they let go in the boat the ignition retards the exhaust gets hot as hell, the engine shuts down and it won't start.

So check it out while you're working on things. Your compression loss is a much bigger problem :)bulb

S CP :D
 

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sucked valves

i recently had a similar deal, but mine hit 0 compression on a couple cylinders!!

i am just wondering if yours could be partially tuliped?????

if your taking the heads off anyway, make sure your valves are alright!!
 

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Discussion Starter #9
it still runs good, i couldnt tell that there was low compression till i did the check
 

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I would take it apart and change bearings,rings, etc while it still runs. Save yourself some major problems. 460 Ty's don't like over heating let alone seizing.
I would bet that parts are crystallized from that ride.
 

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Discussion Starter #11
pulled spark plug and put 120 lbs air pressure into it and it held, no air coming from valve cover so i know the rings are good, i pulled the head off and found the head gasket does have a couple bad places in it, so, hopefully that was my problem, previous owner used a normal head gasket, i going to put a high dollar marine gasket in and see if that wont fix it...........
 

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pulled spark plug and put 120 lbs air pressure into it and it held, no air coming from valve cover so i know the rings are good, i pulled the head off and found the head gasket does have a couple bad places in it, so, hopefully that was my problem, previous owner used a normal head gasket, i going to put a high dollar marine gasket in and see if that wont fix it...........
Have the heads surfaced before installing the new head gaskets. If it got hot there is a good chance the heads are warped and if you just change gaskets only you will be changing them again very soon.
 

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While it's apart check the pin in the dizzy to make sure it's not sheared or at least started to shear. When they let go in the boat the ignition retards the exhaust gets hot as hell, the engine shuts down and it won't start.

So check it out while you're working on things. Your compression loss is a much bigger problem :)bulb

S CP :D
This post is useless without charts! :D
 

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Discussion Starter #14
well guys, got the heads pulled off and the side with low compression found 2 cracks and a seat that was fixing to fall out, 1 crack (between intake valve and exhaust valve was a minor one that could be repaired but when we saw the 2nd crack its beyond repair (another boat anchor) so i found some heads on ebay (cheap) and a buddy of mine owns a head shop and i handed them over to him, did a valve job and worked them over a lil hint hint...... got it put together today and it sounds sweet so looks like yall going to have to put up with me at okmulgee cause I'll be there now...................
 

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Discussion Starter #15
i took it to the lake today for a test drive (water hose in front yard wasnt satisfying enough lol) and it ran great, it run 5200 rpm's at wide open throttle which according to the chart is 450 hp, so I'm happy with that....only thing is I cant get it to idle below 900 rpm or it will die, it only has a 570 cfm carb on it i'm going to try a 750 cfm double pumper on it to see if it will run any better....
 

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i took it to the lake today for a test drive (water hose in front yard wasnt satisfying enough lol) and it ran great, it run 5200 rpm's at wide open throttle which according to the chart is 450 hp, so I'm happy with that....only thing is I cant get it to idle below 900 rpm or it will die, it only has a 570 cfm carb on it i'm going to try a 750 cfm double pumper on it to see if it will run any better....
Most jet boats with a mild cam won't idle that low anyway. Plus, low speed steering sucks any lower than 1,000 RPM. Some guys will idle them closer to 1500 and use the forward/reverse to control their speed in the no wake zones so that they don't have to keep their foot on the gas to get decent steering. Jet boats have to have thrust to turn and anything lower than 1000 RPM wouldn't make enough thrust to provide decent steering.


And yeah...I'd say you're WAY undercarbed on that 570. Reverse the 5 and the 7 and that should be perfect for your setup. :D
 

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Discussion Starter #17
well guys a buddy of mine handed me a Barry Grant 750 cfm double pumper carb and told me to stick it on my boat and see how it acts, I'm hoping it'll open her up a little and breathe a little better than that 570 did
 

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did you have the throttle butterflies 100% open when you did the test?. Could be giving you some bad #'s otherwise.

Good luck!

GT :)hand


WTF???? Noone told me to have the butterflies all the way open when doing a comp test... AHHHHHHRRRRGGGG:|err


Explains SOOOO MUCH now..
 
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