New Member needs help 1997 5.7L Alpha 1

[mikechm3]

Hello all! I have a 1997 Merc. 5.7L Alpha1. I just finished a series of maintenance including new plug wires , cap, rotor, sensor upgrade and new plugs. I also had the carb rebuilt by a local mechanic.

My problem is when i have been out for a while stop and sit or fish, then go to restart. She turns over for about 10-20 seconds and only starts when i give 3/4 neutral throttle. This never happend before, she used to start raight up. Any suggestions?

Thanks!

 

[Bondo]

Re: New Member needs help 1997 5.7L Alpha 1

and only starts when i give 3/4 neutral throttle.

Ayuh,.... Welcome Aboard,... It sounds like a Carb issue...

 

[Alpheus]

Re: New Member needs help 1997 5.7L Alpha 1

Check your choke and make sure it is not sticking.

Is it having any trouble idling?

 

[mikechm3]

Re: New Member needs help 1997 5.7L Alpha 1

Hey thanks for the replys, I'll check the choke later today when i get out. Once I get her started she usually idles pretty good, i troll a lot too and usually no problems trolling at idle speeds for hours. My buddy noticed a puff of dark smoke out from the water the other day when i was having one of my troubled hot starts.

Thanks again.

 

[John_S]

Re: New Member needs help 1997 5.7L Alpha 1

My buddy noticed a puff of dark smoke out from the water the other day when i was having one of my troubled hot starts.

Choke is possible. I assume you also followed the merc service manual and had it in base mode to set the idle mixture and idle rpm.

It also may be gas running down the carb during the heat soak. When the carb was rebuilt, was the same style base gasket used? If a thinner one was used, more heat may be transfered to the carb and causing fuel to perc out, and run down the intake into the cylinders. Opening the throttle would help clear a flooded condition.

 

[mikechm3]

Re: New Member needs help 1997 5.7L Alpha 1

Hey thanks, i'll check the choke first then reset the idle mix and idle rpm to the book specs. I just bolted it on and it seemed to run fine at the marina but obviously things change once things are warmed up. The gasket on the other hand im not quite sure of the thickness in comparison to the original. Is there any way to inspect or test the carb for these symptoms?

Thanks.

 

[John_S]

Re: New Member needs help 1997 5.7L Alpha 1

Is there any way to inspect or test the carb for these symptoms?

After you have run it for some time, and shut it down. Remove flame arrester and watch to see if fuel is running down the carb. This may take 10 minutes or so, for the heat soak to happen. It also may be just cool enough with the cover lifted, it doesn't happen.

Before doing this check, complete the adjustments you mentioned and retest.