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Old 09-01-2010, 08:29 AM   #1
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Default 5.7lt hard to start after a small run and 30min sit but still starts

hi guys , i took my 2400scr with 5.7lt carb engine out last week end and every time i stoped i found it took 20 to 30sec to start ? but when i do a first start up it starts up 3 to 5 sec?? has any one had this problem??. someone told me it could be my lifters loosing pressure, but if that was the case it should take the same to start first time after sitting 2 to 3 weeks??? thanks.........................
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Old 09-01-2010, 01:49 PM   #2
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Fatboy (sheeesh, difficult addressing you, what's your real name!),

Not sure where people come up with some of these ideas but I assure you that the hard re-start symptom is not a result of your lifters loosing pressure.

Question: How much time passes between shut down and restart attempt(s)? 2 minutes, 5 minutes, 30, 60, etc? Does it happen every time? Easily reproduced? Give me a scenario.

Dan
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Old 09-01-2010, 11:26 PM   #3
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hi dan its Ben,
it might be sitting for 10min to 2hr as for re-star 2 to 5 min rest in between cranking
and it happens everytime but say i go for a run 20min then shutoff for 1hr it will take me 20to30sec to re-start at full cranking non stop but once its starts no problems,
but after i trailer it home 30 to 40min to flush it out it starts with half a crank?? and first start it only takes half a crank to start

thanks Ben................
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Old 09-02-2010, 01:24 PM   #4
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Given the symptoms you've described Ben, two possabilities immediately come to mind.

1) It almost sounds like vapor lock, which happens when the gas in the fuel line from the fuel pump to the engine gets heat soaked. Engines actually get hotter when you shut them down. Have a look at the line from the pump to the carb (it's probably a metal line) if it is routed close to the engine block. A quick and dirty test is to wrap the line with wadded up tin foil. The foil will reflect the heat, and having it crinkled up will create small voids where air gets trapped and further insulates the line.

However, since you mention you experience the symptom a hour after shut down, that line should have cooled sufficiently by then so I don't think that's the problem.

2) I think the carb may be leaking gas into the engine after shut down, thus flooding the engine. When this happens the intake manifold plenum, just below the carb, pools with gas, the engine gets hotter after shut down, that pooled gas vaporizes but remains trapped in the intake because the carb throttle blades are closed. When you try to restart the gas/air ratio is way off - too rich, and the plugs can't fire it. So, a quick test. Run it until it's warmed up then shut it down. Wait for oh, say, 10, 15, 20 minutes - or 1 to 2 beers. Before attempting to restart depress the neutral button on the throttle/shift control so that you can open the throttle without the drive being in gear. Open it all the way and then hit the key. If the engine starts quicker then you've found the problem (the carb float/needle/seat). Once the engine starts be quick to pull the throttle back to idle, least you over rev the engine. You could also run it, shut it down, then quickly remove the flame arrestor from the carb and, with a flash light, look into the carb for signs of gas bubbling/dripping, etc. There should be none.

Oh, thought of something else. You did not mention what type of ignition system the engine has but if it's the type that has an electronic module inside the distributor there is a good chance that the EM is becoming heat soaked, rendering it inopperative until it cools off. Very common.

Good luck, let us know what you find.

Dan
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Old 09-02-2010, 11:16 PM   #5
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thanks , i will try it this wekend and i will have a look at the em and let you know what happend
thans Ben...............
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Old 09-03-2010, 12:50 PM   #6
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Did we establish whether this is a carb or fuel injected engine? I think it would help to confirm that first.
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Old 09-05-2010, 03:15 PM   #7
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hi , it was a carb engine
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Old 09-06-2010, 07:57 PM   #8
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I'll have an 1992 Maxum SCR 2300 with the exact same problem, and my mechanic told that I need a new carb kit, my motors runs at 400 to 500 RPM on iddle, no problem at all when I cruise with it, its only when I shut the motor for few minutes, like when i did more than one locks, everytime when I start it back it took me 10 to 15 sec before it fire on ... So I wait for the end of the season before a big tune up ... I hope this is help!
Hey Fatboy (Ben) let me know if you fund the problem!
Thanks
Erik
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Old 09-09-2010, 07:40 AM   #9
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hi ,
so le miss tiffany did this fix it??
i wend out this week and i tryed to start it with some throttle but still same problems , i ended up just cranking it over untill it started but once it did i was fine but then wether turned to 7ft waves and it was a long slow drive back to dock.
i also spoke to a v8 rep today ad he said the float might be getting soaked?? he said i should rebuild the carby ,has any one herd of this
thanks Ben...................
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Old 09-09-2010, 01:09 PM   #10
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Don't try it with some throttle Ben, try with ALL throttle - IE; completely wide open. If the engine is getting "flooded" with gas then the gas to air ratio is way off and the spark plugs can't fire the rich mixture. Opening the throttle all the way allows more air into the engine thus bringing the gas-to-air ratio back in line. As I said thou, just be ready to pull the throttle back if the engine does start.

The Rep you spoke to is correct. Inside the carb is a chamber that holds gas. Also in that chamber is a float. As the fuel pump sends fuel to the chamber in the carb the float rises within the chamber and eventually rises high enough to stop the flow of gas using a sub-assembly called a needle and seat (works exactly like the float in a bathroom toilet). If the float gets a hole in it, or becomes saturated with gas, it won't float so it won't stop the flow of gas into the carb so the carb over fills and the excess spills into the engine.

Frankly though, you don't have enough information yet to point to carb problem, or specifically a problem with the float.

Dan
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