Motor Mis
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=891
Printed Date: November-22-2024 at 7:52pm
Topic: Motor Mis
Posted By: Guests
Subject: Motor Mis
Date Posted: October-08-2004 at 2:30am
I have a friend,,,With a stingRay.with the 454 motor,,,It starts to pop and crack at about 4200 rpms...when you come down below that it runs smooth,,it starts good,,Idles good ,,But at high rpms.starts to cut out,,like it runs out of gas,,,,We have replaced these,
plugs..wires,,dist cap,,rotor Buttom...Fuel pump,,gas lines,,,,Electrical box,,,coil and wire,,,,Run carb cleaner in the carb,,,by past the gas tank with clean gas,,new Fuel filters,,
And some times it will shut down, it he keeps going at or around 4200 rpms,,,we been working on it since april..No luck??? any Ideals..
Thanks Rocco
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Replies:
Posted By: David F
Date Posted: October-08-2004 at 1:23pm
Sounds like a classic example of fuel starvation. Fuel starvation usually has one of three causes:
1. Low pressure fuel line sucking air. If you are using USCG fuel line, it is heavy walled and thus critical that the proper size hose clamp be used at all connections. If the clamp is too large, it clamps the hose in an elliptical shape that allows air in.
2. The fuel line pinched due to too sharp of a bend.
3. Clogged fuel filter or some other type of fuel restriction such as a clogged inlet screen, etc.
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Posted By: Tim D
Date Posted: October-08-2004 at 4:34pm
Check the timing. Sounds like when it's advancing at the higher rpm's it is throwing fire to the wrong cylinders. My mustang ran perfect when I got it, but if you ran it above 3,000 rpm's for about a 1/4 mile, it would make a "running down" sound ending with a pop. Had the timing checked and it was way off.
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Tim D
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Posted By: nms1991
Date Posted: October-09-2004 at 12:05am
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It could be something in the carb, but what brand of marinization is it ie.(mercruiser, indmar, pcm, other)
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Posted By: IrishFooter
Date Posted: October-09-2004 at 5:57pm
If you have a mechanical advance, I would chech to unsure that you springs are working properly. A simple way to do this is to turn the rotor with your hand and ensure that it comes back to where you started. If the advance is working improperly it can throw your timing way off at higher engine speeds. But if its coming back to idle this may not be the case. Easy to check and I would bet it is an ignition issue.
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1979 Ski Nautique
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Posted By: 79nautique
Date Posted: October-11-2004 at 12:48pm
I would double check the timing and make sure that the total advance at higher rpm isn't to high which is most likly your problem. Not sure exactly what the 454 base timing is 10-12 but Also check the mechanical advance and make sure the springs are not weak or stretched (sp). Check a manual and find out what the max total advance and at what rpm and set accordingly. You may have to replace the mechanical advance springs. What yr engine is this?
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: Guests
Date Posted: May-20-2005 at 3:12am
Well,The worry is over,,,We had replaced everything outside of the motor..
We ordered a New Carb,last Tuesday,,put it on and it did the same thing as last year???
while setting out on the water,,I started looking under the dash,,and guess what,it was a Dam wire loose on the Key switch,,,Loose enough.to shake and cut the switch off and on.while moving......He spend $1300 bux on a tune up...But it was a .99 wire......
Runs like a top now...You never know...
Rocco
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