• RECEIVE THE GIFTS MEMBERS SHARE WITH YOU HERE...THEN...CREATE SOMETHING TO ENCHANT OTHERS THAT YOU WANT TO SHARE

    You know what we all love...

    When you enchant people, you fill them with delight and yourself in return. Have Fun!!!

Sign in to follow this  
dunnym

50 hp mercury

Recommended Posts

Hey everyone

so i have a 79 mercury 50 on my fishing boat. Took it out today for the first time this season. Fresh gas, new plugs. It will start and run, then seems to starv for fuel and dies. I can keep it running if i keep squeezing the primer bulb. How do these motors pull fuel from the tank? I cant seem to find any kind of fuel pump? I am using a old school 6 gallon steel gas tank. Anyone have any thoughts?

if i disconnect the fuel line from the carbs, should there be fuel flowing out of the line with the motor not running?

Share this post


Link to post
Share on other sites

Have you checked that bowl thing on the side with the screen in it? Happened to me one time and I think that had something to do with it.

I messed around with some stuff and the problem went away. The bowl and screen had some crud in it.

Share this post


Link to post
Share on other sites

I havent done that yet. I think i will pull the carbs off tomorrow. I had the carbs went thru 2 years ago and always run non oxy fuel

Share this post


Link to post
Share on other sites

Before I would do that, I would check for any type of vacuum leaks and check the fuel hose. Same thing happened to me but smaller engine and it turned out the primer bulb had gone bad. I think the check valve in the bulb would not hold pressure. As long as I pumped the bulb it would run fine

Share this post


Link to post
Share on other sites

Loss of pressure in fuel delivery system from pinhole in bulb, gas line as mentioned, or in the diaphragm...which is my guess. Put your fingers under the carb diaphragm and pump the fuel bulb hard, if you get fuel on your hand, your diaphragm is leaking. Check your gas cap for proper sealing, too.

Share this post


Link to post
Share on other sites

Do you have 6 gallon tank? That vintage motor needs the vent to OPEN I believe, our 82 does. It will do the same thing if that little silver screw cap on the metal tank rattles shut/tight. That is first thing I would check, next would get a BRAND NAME (meaning merc) new hose and bulb. Don't get cheap one from FF or Gander. It will cost more, but go a dealer and get the good one, but make sure it is merc brand and ideally with new metal fittings on the end.

If that doesn't do it, then you need more help than I can give smile but in the 33 years we have owned ours, the above has fixed every hiccup we ever had with similar symptoms. Good luck!

Share this post


Link to post
Share on other sites

I'm going to agree with Box since your bulb isn't holding pressure,check the vent 1st.Then I would look at the hose for a pin hole or maybe just a loose clamp on the bulb or end fittings.Do you have another gas line you can try?If it's the old metal 6 gal gas can check the fitting on the can also as they have a old style cork/paper gasket that dries up & crumbles also.

Share this post


Link to post
Share on other sites

Thanks, that gives me a few options to check out tomorrow

Don't forget the plastic filter? bowl on the side of the motor. You can watch it while running the motor to see if fuel is there or not. I still think it could be that screen in there.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this