fuel pump rebuild needed?

[keithems]

as noted elsewhere, i recently r, r, and r-ed my a4. until yesterday i had been running it off an outboard tank / primer bulb combo attached to my primary filter, thence to the mechanical fuel pump, carb, etc. Motor ran fairly well, but you had to give the bulb a few squeezes every 2 minutes or so.

yesterday, i reconnected the main tank. Flushed it with fuel using the fuel pump priming lever...cloudy at first -- no surprise -- then it cleared. Motor started, ran fine for about a minute, then slowed, then quit. Would only restart if i worked the priming lever until stiff.

Eventually, i found i could keep the motor running fine as long as i worked the priming lever every 30 sec. or so.

i've tightened everything that can be tightened.

i'm assuming the fuel pump is weak or inop and will have to be rebuilt. no biggie -- but am i correct?

Also, since the motor rebuilders were earnest but not very competent, did they screw something up here also? Is there something internal that runs the fuel pump cam that they may have forgot to reinstall? in which case, i'll install an electric pump and not rebuild the mechanical one.

pls. let me know what you think...

[keithems]

btw....

i have a gallon or so of the cloudy, water logged fuel i flushed thru the tank....

what do you guys suggest i do with it?

i can probably burn some of it in my van, but not all of it....

[ndutton]

Does the priming bail move when the engine is running?

[keithems]

good question, thank you

i'll look when i get to da boat

i also assume i can turn the flywheel with the starting crank and see....

i'm also planning now to disconnect the fuel line to the carb and hit the starter and see if fuel flows -- or can i do that also with the starting crank? would rather not use the ig system with fuel flowing....

[Marian Claire]

If it turns out to not be a problem/missing push rod for the mechanical fuel pump. I would suspect an air leak or a bad primer bulb. Both of these will cause shut down and can be overcome by pumping the bulb. The shortness of the run time makes me think air leak is the most likely of the two. Check/tighten/remove and reconnect every connection. Sometimes just tightening does not do any good. BTDT
Dan S/V Marian Claire

[keithems]

i'm thinking it's a missing push rod / bushing, but i'll know better when i get to the boat.

i don't have a primer bulb on my main tank set up -- just on the o/b tank.

though when i reconnected the main tank yesterday, i did try to add a primer bulb, but i couldn't get it to pump fuel from the main tank.....so i removed it and used the priming lever on the fuel pump.....hmmmmm....

[wmmulvey]

as noted elsewhere, i recently r, r, and r-ed my a4. until yesterday i had been running it off an outboard tank / primer bulb combo attached to my primary filter, thence to the mechanical fuel pump, carb, etc. Motor ran fairly well, but you had to give the bulb a few squeezes every 2 minutes or so.

yesterday, i reconnected the main tank. Flushed it with fuel using the fuel pump priming lever...cloudy at first -- no surprise -- then it cleared. Motor started, ran fine for about a minute, then slowed, then quit. Would only restart if i worked the priming lever until stiff.

Eventually, i found i could keep the motor running fine as long as i worked the priming lever every 30 sec. or so.

i've tightened everything that can be tightened.

i'm assuming the fuel pump is weak or inop and will have to be rebuilt. no biggie -- but am i correct?

Also, since the motor rebuilders were earnest but not very competent, did they screw something up here also? Is there something internal that runs the fuel pump cam that they may have forgot to reinstall? in which case, i'll install an electric pump and not rebuild the mechanical one.

pls. let me know what you think...

keithems,

I had a the same problem.

First, stay away from the main tank until you can completely empty it. Then give it a really good flushing to get all the gunk out. Replace the hoses. There are threads here for that.

AS FOR YOUR FUEL ISSUE:

Remove the hose/connection between the pump and carb on the carb side.

Turn the engine over and observe the fuel flow. This will tell you if the prob is the pump or a clogged carb. I would bet on the carb.

I bought the carb rebuild kit from MM. It is a very easy and not a time consuming project to do. The instructions are very easy to follow.


Remove the carb
Take out all the parts that will be replaced
Have access to compressed air supply
Really clean all the ports w/carb cleaner
Use the compressed air to blow out all the ports
Repeat.

Bill

[wmmulvey]

keithems,

I had a the same problem.

First, stay away from the main tank until you can completely empty it. Then give it a really good flushing to get all the gunk out. Replace the hoses. There are threads here for that.

AS FOR YOUR FUEL ISSUE:

Remove the hose/connection between the pump and carb on the carb side.

Turn the engine over and observe the fuel flow. This will tell you if the prob is the pump or a clogged carb. I would bet on the carb.

I bought the carb rebuild kit from MM. It is a very easy and not a time consuming project to do. The instructions are very easy to follow.


Remove the carb
Take out all the parts that will be replaced
Have access to compressed air supply
Really clean all the ports w/carb cleaner
Use the compressed air to blow out all the ports
Repeat.

Bill

I can E-MAIL you or anyone a complete HOW TO PICTORIAL if you like. It is a WORD DOCUMENT file. Just send me a reply at wmmulvey@aol.com

[67c&ccorv]

I have an early model A4 with a mechanical fuel pump which I rebuilt using MMI's kit...it was simple to do - anyone with the proper tools and a little bit of know how can do it.

Mechanical fuel pumps have been used on engines since day one and have a long record of reliability if properly maintained.

That's why I will continue to use one.

[marthur]

I am a fan of the mechanical pump too as a follower of the KISS principle.

[keithems]

the rest of the story

will write more tomorrow -- pretty wiped out now....

but the fuel pump was fine -- needed the pushrod -- which i found and installed...and things seemed to be fine

on my boat -- c&c 30 -- getting the fuel flow started after shutting it off, emptying the water from the fuel pump and my water separator, etc., etc. is pretty hard and time consuming. however, i kept at it and eventually my a4 was running well....so decided to motor out for a sail. about 6 minutes from the marina...very near the harbor wall...a4 stopped dead....no restart!

as i've mentioned, the $40 or so i've paid towboat us is worth its weight....

they towed me back to my dock. said good nite to the crew and then pulled hoses, filters, etc. to see why no fuel flow....and there was NO fuel flow...finally blew into the hose coming from the main tank [i had had enough bourbon by then to not really care what ever yellowish brown liquid it was i was dealing with ].....it was totally blocked at first but then i could feel it release.....reconnected all the hoses...tightened everything...and ...VAROOM! the guy at the dock across the way who never goes out and/or sails was not happy...but i was!

hopefully...that's the end of the story...but now i won't know for sure till next weekend....

is there a way to really clean out my fuel pickup tube? or better...to drain the tank from the bottom? maybe i should drill a drain hole?

k

[Kelly]

cleaning the gas tank

maybe i should drill a drain hole?k

This question has been asked on the forum before and the answer is always a strong "NO". You should never try to drill into your gas tank unless it is empty, thoroughly cleaned and dried (and preferably off the boat, but I don't know how you could really clean the tank without taking it off the boat first). The risks are just too great with the heat and/or sparks generated with drilling.

In the not too distant past I went through this:

• removed the tank from the boat after having pumped out all the gas possible
• cleaned the tank several times with solvents and finally with lots of water (including putting small quantities of gravel in the tank and vigorously shaking it all up to break up all the gunk)
• in my case I applied a "POR 15" treatment before reinstalling the tank with all new fuel lines

When the tank is off the boat and disassembled, you can really judge its condition well- including the fuel pickup tube. Some have reported serious corrosion on this tube and have even found filters/screens in pieces at the bottom of the tank.

[sastanley]

almost there

keithems,

Now that we seem to be narrowing down the problem(s), if it was me, I'd replace the fuel tank..the gunk you blew out of the pickup is still in the tank and will eventually work its way back into the fuel line you've worked so hard to get open.

I replaced my aging aluminum tank (I actually had a pinhole leak so it was a no brainer for me) with a poly tank from Moeller of similar dimensions and couldn't be happier. If you have the time & your tank is physically in good shape, you can do as Kelly and clean it, but it is important not to reintroduce the gunk into the fuel system..it will happen right at the breakwater near the harbor entrance for sure, and then another $40 to the Tow Boat...

At that rate, about 4 tows is a new fuel tank.

[keithems]

i'm sure you're right

a few hundred for a new tank is no biggie for me

however....

before i r, r, and r'ed the motor, i did not have a dirt / contamination problem with the tank. even now, the fuel i flushed thru yesterday has water, to be sure..but is not that dirty....

so maybe -- with the right additive, i can dissolve the gunk? or if i fill the tank [15-20 gal], it will dilute the gunk? or i can remove the pickup tube and replace it if necessary?

biggest qualm bout a new tank is half the summer's gone already -- and i WANT TO SAIL! i'm tired of playing mechanic..so....

how do i remove the tank? what's involved? mine looks like it's in there forever, and i'll have to cut thru the cockpit floor to get it out...tell me that isn't so! [i have a c&c 30]

the $40 for towboat us covers unlimited towing here for the entire year...though i know they won't be so nice if i'm calling them every weekend

plus...when my a4 quit last summer, i put my old, reliable johnson 9.9 on...not ideal for sure....but will be a good backup till the a4 is 100%.....in fact it probably quit because i had started planning to get the johnson off of there

really, the biggest issue is removing the tank -- who knows how i do that and how difficult it will be?

also....who knows what to do with the dirty fuel i removed?

[Marian Claire]

Keithems I tried half measures, sucking out crud, adding additives, fresh fuel, blowing back thru the system to clear the pick-up tube, changing filters, repeat, etc. All they did was postpone the inevitable and cause me more stressful moments when the engine shut down due to clogs. Granted I fought it for a few years but when I finally pulled the tank and cut into it and cleaned it I knew I had done the right thing. YMMV. Dan S/V Marian Claire