5.7 Hard Start

[H2ONUT]

My STBD motor will start fine from a cold start. Run it for 5 min or even less and it wont restart. Holding the throttle wide open and it will start after several seconds of cranking. After a few seconds it smooths out and runs fine... I dont think its vapor lock. I am going to rebuild the carb and get a new float. Any other suggestions? The carb is a 4bbl quadrajet.

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[dwna1a]

Mark, tomorrow is drink night at the boats. I'm going to ask the one guy that has rebuilt my qjets. I want to see what his answer might be to our issue.

It could be that the fuel evaporates from the bowl or we are running the bowl dry. I really don't know but he might. I will keep you informed.

 

[H2ONUT]

Mark, tomorrow is drink night at the boats. I'm going to ask the one guy that has rebuilt my qjets. I want to see what his answer might be to our issue.

It could be that the fuel evaporates from the bowl or we are running the bowl dry. I really don't know but he might. I will keep you informed.

Thanks! I really think its a flooding issue. When a motor is flooded, the WOT trick is key to getting it started.

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[SCORPIO]

Do a search on core plugs or Welsh plugs. Those are in the bottom of the fuel bowls and tend to leak on older QJ's and can cause a flooding issue. There is a fix for it but I don't recall exactly what it is, some sort of sealant on the plugs I "think".

 

[H2ONUT]

Do a search on core plugs or Welsh plugs. Those are in the bottom of the fuel bowls and tend to leak on older QJ's and can cause a flooding issue. There is a fix for it but I don't recall exactly what it is, some sort of sealant on the plugs I "think".

LOL, I was just reading about this. Problem is that using JB Weld doesnt work anymore. The ethenol makes it soft over time...

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[dwna1a]

Mark he wasn't there tonight, I will see him on Friday and will ask

 

[H2ONUT]

Mark he wasn't there tonight, I will see him on Friday and will ask

Kool! Im in deep with my Whaler project for the next 2 weeks.

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[hottoddie]

LOL, I was just reading about this. Problem is that using JB Weld doesnt work anymore. The ethenol makes it soft over time...

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I rebuilt my Qjets 5 years ago and used JB weld on the Well plugs and so far so good on E10.

 

[H2ONUT]

I rebuilt my Qjets 5 years ago and used JB weld on the Well plugs and so far so good on E10.

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[H2ONUT]

Ok... I pulled the flame arrestor off. Started the motor and the choke opens about 1/4. Shut the motor off at operating temp and the choke closes. It really never fully opens while running. Tried to start it back up and no go. Hold the choke open by hand and it starts right up.

Is the spring for the choke NG?

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[dwna1a]

Mark, we worked on mine today as well. He cleaned the choke spring and did some adjusting. So far, as of tonight, it may have done the trick. He THINKS it has something to do with the spring

 

[hottoddie]

Those thermal spring chokes use the same choke spring as cars that run 195* thermostats. Raw water cooled inboards run 145* thermostats and fresh water cooled run 160* thermostats. Therefore the chokes are very slow to open and sometimes don't ever fully open. I recommend replacing them with electric chokes. Did mine 4 years ago and both 454's start and run they are fuel injected. Chokes fully open in a few minutes.

 

[H2ONUT]

Sounds good. Ill report back in a day or so.

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[H2ONUT]

I ordered a new choke spring. Ill start there and see what happens.

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[H2ONUT]

The screw that holds the spring to the intake snapped. So I removed the choke butterfly from the carb. Starts great every time!

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[CliffA]

So I removed the choke butterfly from the carb.

that may be OK as a temporary repair but personally I would not leave the choke not working for long.....as you probably know the choke is needed to allow the correct fuel/air mixture to feed the engine to provide smooth starting from a cold start.....without the choke working properly the engine will likely be harder to start when cold and will likely run rough until the engine warms up....this will become more pronounced as the weather gets cooler in the fall/winter......

cliff

 

[H2ONUT]

that may be OK as a temporary repair but personally I would not leave the choke not working for long.....as you probably know the choke is needed to allow the correct fuel/air mixture to feed the engine to provide smooth starting from a cold start.....without the choke working properly the engine will likely be harder to start when cold and will likely run rough until the engine warms up....this will become more pronounced as the weather gets cooler in the fall/winter......

cliff

I hear ya! Over the winter Ill rebuild the carb and pull the intake and get the broken screw out. Will do both sides because, well you know how it works... LOL

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