1979 305 OMC/Chevy 200hp fuel pump question

[fabrimacator21]

I'm starting to think my fuel pump is bad.... it' won't start after a carb rebuild and a new fuel filter.

Motor is a 1979 305 OMC/Chevy 200hp

I have a new carter fuel pump that came off my truck but it's a different style then the pump in the boat. The boat pump has a vacuum line going from the top of the fuel pump to the top of the carb (right near the choke blade). The new pump that came off my truck doesn't. Is this a problem? What is that line for? Can I just plug up the line at the carb and use the new pump?


I don't want to spend 100 bucks on a new pump when I have a new one sitting right here.

 

[Bondo]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

The new pump that came off my truck doesn't. Is this a problem?

Ayuh,... That sure is a Problem,... Don't put the truck pump on your Boat...

 

[fabrimacator21]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Ayuh,... That sure is a Problem,... Don't put the truck pump on your Boat...

What does that line do?

No offense but it's kind of hard for me to take your word without knowing what that vacuum line does. If it's critical then I have my answer, but I know that alot of carbs run without that vacuum line from the pump.... . I've been trying to figure out what it does and the best I can come up with is a overflow line or a "helper" to the pump... I.E. the vacuum from the motor helps the plunger in the pump come up. All this is just theory of course.:redface:

 

[jtybt]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

First of all, it's not a vacuum line. It's a line that on an auto pump would be the weep hole. On a car, if the diaphram ruptures, the gas can simply drip onto the ground. You don't want gas dripping into the bilge so the weep hole has a fitting that runs to the carb to safely get rid of leaking fuel.

 

[fabrimacator21]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Would it be possible to drill and tap the weep holes (theres 2 small holes) and run a line up to the carb. I have to do this on a budget.

 

[zbnutcase]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Might be possible but I still wouldn't do it. 'nutcase

 

[jtybt]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

It's not something anyone can recommend...

 

[fabrimacator21]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

okay....

Is there a way to test a fuel pump once you pull it off? It may just need to be primed since the canister was completly empty. I'll try to prime it with compressed air through the fuel fillup and crank it tomorrow.

How about plugging up the weep holes with j/b weld? Or would that cause gas to leak into the crank case?

 

[Bondo]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

How about plugging up the weep holes with j/b weld?

Ayuh,... Are you trying to fix you're boat,..?? Or build a BOMB,..??

It may just need to be primed since the canister was completly empty.

That sounds like a restriction, Up-stream of the cannister...

 

[havasuboatman]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Always fill the water separating fuel filter with gas before you put it on. Aside from the potential fire danger, that is probably your problem.

 

[fabrimacator21]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Ayuh,... Are you trying to fix you're boat,..?? Or build a BOMB,..??


That sounds like a restriction, Up-stream of the cannister...

LOL not going for a bomb.

The canister was empty because I emptied it when I changed the filter.... I should have said that.

 

[fabrimacator21]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Always fill the water separating fuel filter with gas before you put it on. Aside from the potential fire danger, that is probably your problem.

Okay. I'll try that and let you guys know what happens.

 

[PiratePast40]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

When I totally replaced the fuel system, including the tank and fuel lines, I was strongly cautioned against prefilling the fuel filter. In fact, was told that it was a bad idea, dangerous, and totally unnecessary. You might want to seriously rethink what Bond-o said and back track upstream.

 

[havasuboatman]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Who told you that nonsense? You always want to fill that sucker up. What's the first rule of fuel pumps? Don't run them dry. It takes a lot of vacuum to draw fuel from a fuel tank, past the check valve ball into and thru that big canister and finally into the carb or injecters.
Hell, when a motor comes from Mercruiser to the boat factory its already got gas in the water separater.

 

[PiratePast40]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Well guess that's how forums help out I was told not to prefill a water separating fuel filter and that it was a dangerous habit to get into. Was just trying to pass it along. My apolagies - guess I know better now.

 

[bruceb58]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

I can understand if someone said it was dangerous if there was a chance you could spill some of the gasoline into the bilge and started the boat before all fumes were gone.

I always prefill and also vent the bilge A LOT before I attempt to start.

 

[havasuboatman]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

Absolutely, any time the fuel filter is removed fuel is gonna get into the bilge. Always air it out and run the engine with the engine compartment open fully open the first time so you can immediatly see any leaks.

 

[Alpheus]

Re: 1979 305 OMC/Chevy 200hp fuel pump question

I just bought one of these and fixed all of my problems. Part # VG100K

http://www.matcotools.com/Catalog/toolcatalog.jsp?cattype=T&cat=2170&page=2&#61831