2000 mercury 135 vapor lock

[Joe R.]

How do I solve the vapor lock issue? Motor runs awesome! When I shut it down and restart, it starts right up, idles great, put it in gear, hit it and it bogs down. After 3-4 times, runs perfect again! Temp is perfect. Engine had been serviced. Tried different grade fuels and additives, no change. Dynos fine. Any suggestions?

 

[Chris1956]

Well, it should not get vapor lock. You have replaced the waterpump recently? How about the thermostats and poppit valve?

Let her run a minute after a high speed run, before shutting her down. That should help as well.

 

[Texasmark]

Vapor lock is on the inlet side of the fuel pump and caused by hot weather and a restriction on the suction side between it and the fuel supply. When the pump is in the suck stroke it creates a low pressure area that attracts the fuel. If there is a restriction the pressure drop occurs across the restriction, not the fuel, and the liquid fuel turns to vapor. Engine can't run on vapor; not enough BTUs.

My worst experience with it was in a '72 Chevy 400 cu. V8 with a Quadrajet carb. The fuel filter was in the carb and very small. I got the bright idea to put a regular metal can fuel filter preceding the fuel pump (suction side) as the line from the pump to the carb was steel and I didn't want to cut it. Coming home from vacation one summer I learned of my mistake.

HTH,
Mark

 

[Dukedog]

Not a "vapor loc" as in tha ole chevys/ fords etc. Its in tha fuel delivery because something is a touch outta whack. If its not "vapor lockin' on thse 100+, cloudless, no wind days in Texas I have a hard time with "its a vapor loc" thing. On some motors, for what ever reason, after a wfo run and/or sits for any time after motor is shut down tha blub needs ta be pumped before its restarted to prevent this so I've been told. I really don't know what causes this 'cause never seen it first hand in almost 40 years of every type problem with tha V6 Merc/Mariner..........jmo

 

[Faztbullet]

The only time I seen a V-6 vapor lock was in the early 80's and Merc's cure was to drill hole in check valve of fuel pump,,,

 

[Joe R.]

I have squeezed the bulb before restart and it doesn't seem to make a difference. I believe it I'd not vapor lock, but a fuel sending problem. It seems to be "starving" for gas. Once if gets it, all is good.

 

[Dukedog]

Have ya been thru tha fuel pump? Tried tha enrichner when it "bogs down"?

 

[Joe R.]

What is the enrichener? Choke? I'm wondering of the problem is with the fuel line or bulb or something prior to the fuel pump. Boat tech says pump is working properly.