Anyone else with a Mercruiser 3.0 have this problem?

[jimalbert]

Before I go too far let me start by saying that my father in law is probably the best Merc/Mercruiser mechanic in Pennsylvania.  He rebuilt and re-painted my carb, changed the distributor cap, plugs, and wires.  We also changed the fuel filter at the end of last year.  

 

I have a problem where I get to the lake, start the boat (starts perfectly) run to my spot (runs fine WOT and at idle).  However, when i get to an area and shut the boat off and try to restart it I have to advance the throttle and crank her over a few times to get it started.  Were certain there is nothing wrong with the fuel delivery system and there are no leaks.  I am thinking its a vapor lock issue because it gets so damn hot in that engine compartment.  

 

I am faulty of not using the blower when I run and shut off, and i typically dont let it idle for a few minutes when I get to an area before shutting it off.  This thing has a metal fuel line that runs along the starboard side of the engine up diagonally to the top and across the top to the carb on the port side of the engine.  You can buy a replacement rubber hose so I may do that.

 

Father in law suggested (because he thinks its vapor lock as well) wrapping fuel line to deflect heat.  I bought a piece of heat shield wrap to see if that circumvents the problem.  here is the wrap:  http://www.autozone.com/ignition/heat-shield-sleeve/thermo-tec-1-2-to-1-in-x-3-ft-express-sleeve/379541_0_0/?checkfit=true

 

Above and beyond that, I am trying to find a way to get it cooler in the compartment.  Run with the lid open, put a vent in the front and side of the dog house,  etc.  I wish I could somehow do a cold air intake but would have no easy way to get a flexible duct from the front to the back of the boat.  I even thought about putting a fan on the front of the dog box that i could run off of my trolling batteries that i could run while running on the lake to get cooler air in there.  

 

Other things to mention:  I run non-ethanol gas, use a fuel treatment, and it does seem like the starting issue is less when it is cooler out.

 

Just curious if anyone else has this issue with a mercruiser and what you have done to help the situation.

 

Thanks,

 

Jim

Edited August 12, 2016 by jimalbert

[vetting]

So why are you shutting the engine off when getting to your spot?  How long is it shut off when you have trouble restarting it?

 

It could also be that the fuel in the carb bowl is too hot - a spacer between the intake and the carb will fix that.  

[jimalbert]

This isn't necessarily when I'm trolling but when I occasionally go bass fishing or I'm just out hanging with the family. I'll look into the spacer.

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[bout time]

Depending on the year some had electronic chokes. My father had a similar issue and it was the choke hanging up. You'd never know it by looking at the choke but once we replaced it he's been good. Any merc mechanic should be able to at least test the choke to rule it out

[yabmob]

Check the float height. If it is not right the float will continue to put fuel in the bowl and flood the motor, thus the hard starts. After the motor is warme up, pull the flame arrestor and turn off the motor. If you still see gas coming into the carb, you have your culprit.

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[chinook35]

Check the float height. If it is not right the float will continue to put fuel in the bowl and flood the motor, thus the hard starts. After the motor is warme up, pull the flame arrestor and turn off the motor. If you still see gas coming into the carb, you have your culprit.

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this is probably your problem. Do you have mer carb or Rochester ? Float heights are different for the two Also possible problem is float valve. Did you use the viton or solid when you rebuilt. There is a Mercury service bulletin regarding float adjustment on 3.0 liter engines. You can google it

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