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chuck westra
07-11-2012, 10:50 PM
I have what appears to be a vapor lock issue with my 86 prostar. If I shut it off when warm, it can be very difficult to start again. Can anyone offer any solutions? I have already had carb rebuilt and I have insulated gas line from the fuel pump to the carb.

j.mccreight@hotmail.com
07-11-2012, 11:18 PM
Next time your out, pop open the engine cover so it doesn't heat soak and when your ready to go based on your past experience time and see if she'll fire off, if she doesn't start then you don't have vapor lock and need to look elsewhere for your problem.

homer12
07-12-2012, 08:36 AM
what do you guys use to insulate your fuel lines? I may do this as precautionary, sounds relatively easy.

chuck westra
07-12-2012, 10:41 AM
I simply bought insulating tape from an auto parts store and wrapped the fuel line from the fuel pump to the carb.

TRBenj
07-12-2012, 10:59 AM
I think vapor lock on a carbed marine motor has about as much credibility as the loch ness monster.

Pull off your flame arrestor and look down the throat of the carb after you shut the engine off. $5 says its dripping fuel off the boosters. The solution is to replace the needle and seat.

Try opening up the throttle butterflies (WOT throttle in neutral) to get it to start next time. Do NOT pump the throttle- that adds more fuel.

SilviaMan
07-12-2012, 12:53 PM
I think vapor lock on a carbed marine motor has about as much credibility as the loch ness monster.

Pull off your flame arrestor and look down the throat of the carb after you shut the engine off. $5 says its dripping fuel off the boosters. The solution is to replace the needle and seat.

Try opening up the throttle butterflies (WOT throttle in neutral) to get it to start next time. Do NOT pump the throttle- that adds more fuel.

I'll agree with this, and or a float level issue.
(to figure out mine I was behind the boat getting ready to be pulled and I saw the black smoke when she started)

Nvrgvup
07-13-2012, 02:47 PM
I would also look at your ignition system. What thermostat are you running and what is your normal operating temp? I think you should be running a 142 F stat...or at least that's what my 83' runs.

If you have the stock points ignition, I would tell you what I did to resolve my hot restart problems, however I know better and will get slammed. So I will keep quite, and can only tell you in a dark back alley.

JimN
07-13-2012, 03:22 PM
I think vapor lock on a carbed marine motor has about as much credibility as the loch ness monster.

Pull off your flame arrestor and look down the throat of the carb after you shut the engine off. $5 says its dripping fuel off the boosters. The solution is to replace the needle and seat.

Try opening up the throttle butterflies (WOT throttle in neutral) to get it to start next time. Do NOT pump the throttle- that adds more fuel.

Think about what vapor lock is- it's when the gasoline starts to "boil", which starts at about 110F and becomes worse at higher temperatures if the fuel isn't under pressure. That means the gas will create an air bubble wherever it can happen most easily. If it's in the carb and the pressure pushes gas out of the fuel line and into the tank, gravity will cause siphoning to draw gas out of the carb until it reaches the lowest level in the bowl. If the boat has a working anti-siphon valve, it can push the gas into the intake, as you're describing.

JimN
07-13-2012, 03:23 PM
Next time your out, pop open the engine cover so it doesn't heat soak and when your ready to go based on your past experience time and see if she'll fire off, if she doesn't start then you don't have vapor lock and need to look elsewhere for your problem.

+1000

Or, use the bilge blower.