470 vapor locking

[1977 SILVERLINE]

Where does a 470 usually vapor lock at? I have already installed an elecrtic fuel pump between the tank and the factory fuel pump/water seperator. Do they tend to vapor lock in the metal line from the factory pump to the carb or.do.they vaporock in the carb itself? Thanks

 

[Eric 3.7LX Alpha 1]

I haven't had any issues with vapor lock with mine. What symptoms are you having that lead you to vapor lock?

Read this from a 470 forum:
http://www.breezeworks.net/cgi-bin/M...1&TopicID=1550


and this one on the same subject:
http://www.breezeworks.net/cgi-bin/MBoard/forum/display_topic_threads.asp?ForumID=1&TopicID=2015

 

[1977 SILVERLINE]

I never have trouble when the boat is running but when i shut it off ocassionally it will start and idle but when i put it into gear it quits. I restart and push the button to rev the engine in neutral and it will quit. When this happens i open the doghouse cover and let it cool down for 10 minutes and it willstart and run just fine.

 

[SDSeville]

You have an electric fuel pump and the factory mechanical pump?

 

[1977 SILVERLINE]

Yes I have an electric that force feeds the mechanical

 

[SDSeville]

Do you see fuel going up the clear line from the mechanical pump to the carburetor?

Try removing the mechanical pump and just use the electric. I fought what I thought was vapor lock for a few years and it turned out to be a bad mechanical fuel pump. It always started great when cold but would be super hard to start when warm. The diaphragm on the pump was bad and it would flood the carb every time I shut the engine down.

 

[1977 SILVERLINE]

I tried bypassing the mechanical pump last year and the boat acted the same but worse. I have the electric pump wired to an oil pressure switch so if it doesn't have oil pressure pump wont run. With the mechanical pump hooked up at least it can pump until the electric one turns on to take over.