5.7 liter surging, dying, not starting for a while

[thewarden]

1996 gm 5.7 liter(was told 5.7 liter need to verify) v8 2 barrel carb. I just bought this crownline with the current situation this forum has helped a lot so these are my problems and i think i have it narrowed down... cold start good....cold or hot the engine will not rev over 3400-3700 rpms... the engines surges... 3000 rpms runs great but when you throttle down to idle it will die.... if engine surges too long it seems to want to die as well... after it dies it will not start....hour later starts.... when trying to restart it smells flooded.... it takes a while and will finally start after it clears out.... no evidence of water in the oil...previous owner rebuilt carb., still had the problem.... i have put fresh premium gas with b12 cleaner in the tank, changed all fluids and filters, and have begun to assess the problem, the timing seams correct, fires right up on cold start, tomorrow i will hook up guage for fuel pressure, and look at distributor cap, and coil,,, i need to change plugs and gather more information but the exhaust manifold seams to be in the way,, another problem i am having is the throttle shifter does not go into neutral sometimes, i have to go to reverse to hit neutral and then bring it back... is there any adjustment??? any ideas will be appreciated

 

[Glasply]

Re: 5.7 liter surging, dying, not starting for a while

Wild azz guess? Vapor lock from a hot fuel hose or filter mount? Check the fuel check valve. If it's gummed, you've got a restriction on the vac side. Add some heat to the lines by running a while, and pretty soon you're boiling the gas before it can get to the pump. The flooded smell could be the dumped contents of your accelerator pump steaming up. Just guesses.

For your shifter situation, look at posts regarding "shift interrupt switch", could be a grounding issue, could be that your idle is way high to keep from stalling and as a result the engine doesn't "die" enough to allow it to come out of gear.

 

[Bondo]

Re: 5.7 liter surging, dying, not starting for a while

.previous owner rebuilt carb., still had the problem....

Ayuh,... Sounds like he screwed it up,...

Try it again...

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

where is the fuel check valve? i do have vapor come out of the carb., occasionally when in no start situation,, so could i be on the wrong track with fuel pump or distributor?... idle seems to be low enough to engage neutral, will check out that thread....... i am considering rebuilding the carb again to make sure it is correct and was originally hoping new gas, and filter, along with tweaking, or rebuilding carb.. but after all the information overload it seems to be that a lot of things could create this condition... thanks for all of the info... do i need to remove exhaust manifold to remove spark plugs,,havent tried yet but it looks tight and dont think i will be able to get a socket on them

 

[rickryder]

Re: 5.7 liter surging, dying, not starting for a while

You can reach the plugs with an extension and socket.....they angle slightly downward.... no need to remove manifolds.

 

[Eric 3.7LX Alpha 1]

Re: 5.7 liter surging, dying, not starting for a while

Ayuh,... Sounds like he screwed it up,...

Try it again...

Ditto on that ^^^

I have seen the needle valve installed incorrectly where it hangs on the float and won't seat correctly causing flooding. (in the attached photo it shows not to hook the clip from the needle in the holes on the float bracket). Just something to look for.

Here are some videos for you to watch from Alpheus- How to Rebuild a Rochester Quadrajet:
http://forums.iboats.com/showthread.php?t=362542

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

wow that was quick i like this site

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

my carb looks different that is a 4 barrel correct? mine is a two barrel and as soon as i saw that i thought 5.0 liter,,,,i guess i will check the numbers..

 

[Eric 3.7LX Alpha 1]

Re: 5.7 liter surging, dying, not starting for a while

my carb looks different that is a 4 barrel correct? mine is a two barrel and as soon as i saw that i thought 5.0 liter,,,,i guess i will check the numbers..

It is a pic of a 4 barrel, but I have seen the issue on 2-barrels as well.

 

[Don S]

Re: 5.7 liter surging, dying, not starting for a while

You have the 2bbl Mercarb, here is the manual, that has a section on that particular carb. http://www.4shared.com/document/Kgl-Dq7d/Service_Manual_17.html


Here is a Mercarb service bulletin you should read.

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

o.k. so i pulled carb and cleaned it there was some trash in it,, problem is still there,adjusted carb, problem still there,, removed fuel pump and cleaned it,, pretty nasty stuff inside and rubber line that goes from pump to carb was clogged,,, replaced line cleaned pump and put back together,,, problem is still there,, engine surges about 3700 rpms and will not go up anymore as a matter of fact during surge rpms start to go down,,,

 

[dubs283]

Re: 5.7 liter surging, dying, not starting for a while

is there fuel in the clear line between the fuel pump and the carb??

have you looked into carb immediately after shutting the engine off??

did you read the service bulletin put up in post #10??

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

the line was clogged when i cleaned out the fuel pump i changed the line with a black one cant see it havent pulled it off after restart,,,,, i have read the bulletin many times and how can i tell if my ignition is a thunderbolt v ??? the answers to the questions are

1. yes
2. yes
3 yes unless mine is thunderbolt v then need to do it again
4. 1 1/4 turns and have tried different adjustments
5. yes
6. will check venturi output at 2000 rpms today but it was ok
7. yes
8. no

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

i have looked in the carb. and after running the engine up to the problem area backing it down and killing it, the venturis drip a little gas is that normal,,, bulletin is saying replace jets on the smaller engines and the venturi on the 5.0 i will check numbers of everything be back soon

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

o.k. the block number is 14096284 gm
2
carburetor is a 807312
5503

with a 468 venturi
carb. has recently been rebuilt not sure what jets are in it

i sure dont want to just go replacing parts,,, please help

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

oops thats the intake number not block number

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

serial number f769632

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

how do i tell if i have a thunderbolt v ignition,,,,1996 crownline 210 ccr 5.7 liter mercruiser 2 barrell carb. and how can i tell what outdrive is on it,, does not say

 

[thewarden]

Re: 5.7 liter surging, dying, not starting for a while

it is not a thunderbolt v,,, changed fuel pump, distributor cap and rotor, replaced pugs and wires, retarded and advanced timing,, retarding made it pop through carb more, advance made it surge more adjusted air/fuel mixture with timing,,,, i have the coil and coil pickup coming,, i am at a loss dont know what else to do,, bulletin doesnt talk about jet or venturi on 5.7 but i will take it apart again and triple check the carb... i live in oklahoma what jet should i use at 1000 feet above sea level? would that cause this condition?

 

[Bondo]

Re: 5.7 liter surging, dying, not starting for a while

i am at a loss dont know what else to do,,

Ayuh,... A Compression, 'n leak-down test....