Author Topic: Strange Fuel Related Problems  (Read 1510 times)

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Offline thewillets

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  • 1965 Futura 500 V164
Strange Fuel Related Problems
« on: August 01, 2022, 03:43:21 PM »
My fuel pump crapped out and sprung a leak along the gasket so I replaced it.
When doing so I replaced the Rube Goldburg lines and connectors with new lines and connectors to simplify the setup.
I also rebuilt the carb and replaced the needle/seat and accelerator pump, as well as the bowl gasket.

Here is the weird part, it fires up and runs well but will suddenly stall and it will require choke to get fuel again.

I am pretty sure I adjusted the float pretty well (but maybe not) !
It seems like the new pump must be working because it fires up and runs (with a LOT of choke at the beginning).

Here are the more nitty gritty details :

Fuel line from pump now runs directly to a TEE at the carb, bypass line branching back to a TEE where the tank runs into the filter (bowl type), then back into pump.

Seems like a fairly standard arrangement but maybe the TEE should be between the filter and pump ?

Should there be any restrictor in the bypass line to assure higher pressure directly into the carb ?

Not my first rodeo but this one is puzzling, I plan to temporarily remove the filter from the bowl (easiest first step).
I guess the next thing would be to check the float (maybe it is sticking closed or adjusted improperly).

I appreciate any additional insight provided.

Thanks,
Neil

1965 Futura 500 V164

Offline Plugcheck

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Re: Strange Fuel Related Problems
« Reply #1 on: August 01, 2022, 04:27:29 PM »
Im confused by the tee at the carb?   Non fuel injection systems do not require a return line.     Your pump, hopefully marine rated, will have internally two diaphragms, one for fuel pumping, the other to contain fuel if the first diaphragm fails.   This second port generally has a line up to the carb connecting to the carb or air cleaner.   Its a solution far better than dumping fuel in the bilge.    Im wondering if these lines are somehow mis plumbed?    Another would be to check the fuel well level, float settings.   
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline thewillets

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  • 1965 Futura 500 V164
Re: Strange Fuel Related Problems
« Reply #2 on: August 01, 2022, 04:59:56 PM »
Not sure why it is like this but I have looked at other similar boats and they also used a TEE to return to the input side of the fuel pump.

The fuel pump just has one input and output, and I am only replicating what was already there (minus the odd collection of connectors).

I don't want to eliminate that because I am worried about too much pressure overpowering the needle/seat.

The tank is just a tank, no return line or anything, 1/2 full right now.
1965 Futura 500 V164

Offline aquamaniac

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Re: Strange Fuel Related Problems
« Reply #3 on: August 01, 2022, 07:22:32 PM »

Offline Plugcheck

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Re: Strange Fuel Related Problems
« Reply #4 on: August 01, 2022, 09:36:23 PM »
The supplied document explains how it works with restriction in the bypass line.   I suppose as a means to limit pressure?    Interesting set up, curious to know of you could just add a fuel pressure regulator and eliminate the bypass, but not certain if pressure would build at the pump outlet and cause more problems.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline thewillets

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  • 1965 Futura 500 V164
Re: Strange Fuel Related Problems
« Reply #5 on: August 02, 2022, 10:10:05 AM »
I looked at the parade of connectors (Rube Goldburg) collection that I took off and one of the connectors actually is a restrictor !

It is a brass connector but inside is blocked off except for a pin hole !

So I guess I need to figure out a way to plumb this into my bypass line, it has an odd compression connection but I will find an adapter.

I am still concerned that the fuel pump I purchased is for a car and will have too much pressure, from what I am finding boat fuel pumps were 5-6 lbs and cars were 12-14 lbs pressure.

I got my replacement at the auto parts store not knowing any better.  It looks pretty much the same but I don't have a good way to read the pressure.
1965 Futura 500 V164

Offline Hyperacme

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Re: Strange Fuel Related Problems
« Reply #6 on: August 02, 2022, 01:55:28 PM »
I think you want a marine fuel pump .. someone can explain .. I've heard details but can't remember .
Rich had some kind of set up to cut stuff off when something screwed up. I think ..
I'm searching for topic ..

Offline Plugcheck

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Re: Strange Fuel Related Problems
« Reply #7 on: August 02, 2022, 03:37:11 PM »
Id suggest a marine electric fuel pump and abandon the mechanical, but you already have some money tied into the current components.    I suspect the design with the restriction was to bleed off excess pressure while at higher rpms.    You might find success getting that back together since you found the restrictor hose/device.   
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline thewillets

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  • 1965 Futura 500 V164
Re: Strange Fuel Related Problems
« Reply #8 on: August 03, 2022, 09:48:07 AM »
I looked at the diagram (Thanks for that link, very helpful !).
I added the restrictor to my return line (per the diagram).
I plan to test it this evening, still a little worried about excessive pressure on the input to the carb.
My only comfort is that it is basically a Nova II motor and the carburetors are pretty much identical.
I guess I will find out soon enough .....
1965 Futura 500 V164

Offline thewillets

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Re: Strange Fuel Related Problems
« Reply #9 on: August 04, 2022, 08:57:22 AM »
Winner Winner Chicken Dinner !

Fired it up last night and it didn't even miss a beat.

Ran it for 20 minutes in the driveway and tuned the carb, it has never run better.

A little history, my dad purchased this boat from the original owner back in the early 70's.
It always started hard when cold but ran OK so I never messed with the carb or fuel lines.
When I took the carb apart I noticed the brass float was held by the pivot pin thru only 1 of the holes ...
After further examination I noticed that the float was soldered OFF Center on the pivot !
I can't be sure but I think it may have come from the factory like that, you could see where it had rubbed for years.
Fortunately I had a spare carb sitting around that I opened up and stole the float (not off center).
I replace the needle/seat, the dried up accelerator pump and gasket - cleaned it all up and now it works better than ever.

I want to thank you all for your advice and assistance !

Hope to see you all at the meet, assuming that Blake invites me and not his friends/girlfriends/etc.

Regards,
Neil
1965 Futura 500 V164

Offline Hyperacme

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Re: Strange Fuel Related Problems
« Reply #10 on: August 04, 2022, 09:08:33 AM »
Hope you can make it to the meet ..
AND .. hope ya look good in a speedo swimsuit ..   :o  :o  :o

Offline Plugcheck

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Re: Strange Fuel Related Problems
« Reply #11 on: August 04, 2022, 09:19:13 AM »
Glad to hear all is well now.  Learned something new along the way as well.
Michael
1979 CVZ-18 388 CI Vortec Mouse
1980 CVX-16SS 140 Mercruiser
1979 CVX-16 Johnson 175
2002 Bennington 2275CC 90 Mercury
1985 Intimidator project
1989 Lowe 200 Redneck fishin Toon
2001 Godfrey Sweetwater pontoon 115 Rude

Offline thewillets

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  • 1965 Futura 500 V164
Re: Strange Fuel Related Problems
« Reply #12 on: August 05, 2022, 08:55:33 AM »
OK, that is just scary !
1965 Futura 500 V164

Offline Hyperacme

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Re: Strange Fuel Related Problems
« Reply #13 on: August 05, 2022, 04:00:57 PM »
There was a few guys coming from Europe to this years meet .. UNTIL they saw that picture   :o  :o  :o