Fuel line/filter Bulb question??

Gomer50 · Oct 25, 2009

I have rebuilt the carbs,rebuilt the fuel pump all looks good and runs,but it still seems to be not getting enough fuel.I have replace the bulb and fuel filter.So here's the question when I pump up the bulb I can see the fuel come through the filter but it never fills up only maybe a quater,when running its empty,I am thinking somewhere in this neighborhood is where my problem is.Not getting enough gas???? Any suggestions...

j_martin · Oct 25, 2009

Re: Fuel line/filter Bulb question??

My crystal ball is failing me. What engine are you talking about?

Gomer50 · Oct 26, 2009

Re: Fuel line/filter Bulb question??

LOL good one.1972 Mercury 800 thunderbolt outboard.I gotta remember that one,I guess I posted a couple of times regarding this motor and was thinking well I guess I wasnt.Anyway after pumping the bulb shouldnt the filter which is before the bulb get full and then stay that way when the motor is running.
Fuel tank--fuel line-- filter-- fuel line-- bulb-- fuel line--Engine,,I am guessing somewhere from fuel tank to the bulb is the problem.I think I should just buy a new fuel line and bulb + fuel filter.And I am guessing while I do this I might as well go ahead and make sure the fuel tank is clean as well.Whatcha think about that???

rosser1 · Oct 27, 2009

Re: Fuel line/filter Bulb question??

you could, that would be a good start, and check fuel pump diaphrams, may be hard and not workin right. bulb may not suck gas throw filter. move it to where bulb pushes fuel into filter, try and see if not put it back your way

Knightgang · Oct 27, 2009

Re: Fuel line/filter Bulb question??

You have the filter onteh wrong place if you want it to fill up with fuel. There is a valve in the bulb to keep fuel form flowing back to the tank. Your setup. tank - line - filter - line - bulb - line - engine there is nothing to keep the fuel form leaking back into the tank. Move your inline filter to between the bulb and the engine, should see much better results...

Knightgang · Oct 27, 2009

Re: Fuel line/filter Bulb question??

THinking back to when mechanical fuel pumps was on cars, before the elctric pumps on the tanks, the fuel filter was between the pump and the carb. I would try the filter between the bulb and the engine, if it does not work, I would suspect that it may need to be a smaller filter and go between the fule pump and the carbs...

Gomer50 · Oct 27, 2009

Re: Fuel line/filter Bulb question??

Thank you for your reply I think I will give that a go,first I will go buy new line, filter, and bulb and put in this order tank-line-bulb-filter-line-motor and give it a try.Thanks

sschefer · Oct 28, 2009

Re: Fuel line/filter Bulb question??

Filter location should be after the pump and just before the first carb. The filter will fill about 1/2 - 3/4 when the engine is running. To test your current setup, remove the bayonet fitting that connects the fuel line to the engine. Place the open end into a fuel safe container and squeeze the bulb. If you have a good solid stream develop after a few squeezes you should be good to go. If the stream is weak and the bulb colapses and doesn't recover fairly quickly then you have a blockage or a bad bulb. If the fuel appears aerated then your sucking air in from somewhere.

If all else fails remove the stock fuel pump and put a Holy Red Marine electric pump, a holy pressure regulator and fuel pressure gauge in and never squeeze a bulb again.

j_martin · Oct 28, 2009

Re: Fuel line/filter Bulb question??

Knightgang said:
You have the filter onteh wrong place if you want it to fill up with fuel. There is a valve in the bulb to keep fuel form flowing back to the tank. Your setup. tank - line - filter - line - bulb - line - engine there is nothing to keep the fuel form leaking back into the tank. Move your inline filter to between the bulb and the engine, should see much better results...

I disagree. If everything is tight, and the bulb is after the filter, the check valve in the bulb will keep the fuel from flowing backwards.

On the filter. The filter will fill up until the exit line is covered. On a cartridge filter laying on it's side, that's about half full. If it is inverted it will be less than that.

If the filter is right, and it is not filling to the exit line, then there is an air leak in the fuel line or pickup tube before the filter. Dip tubes in the tank are famous for this.

I'm running a screamin' v6 with the original pulse pump on the motor on this rig. Tank, Racor fuel filter/seperator, line, bulb, (skipped the bayonet) line into the oil mixer.

hope it helps
John

sschefer · Oct 28, 2009

Re: Fuel line/filter Bulb question??

John, are you still running oil injection on your XR. If so do you run a 5/16" inline filter between the fuel pump and first carb to catch any dirt that might get into the oil tank? I didn't for a long time until I had a problem with dirt in oil that I bought at Wally World. More my fault than anything. I didn't notice that the seal was broken.

Knightgang · Oct 28, 2009

Re: Fuel line/filter Bulb question??

j_martin said:
I disagree. If everything is tight, and the bulb is after the filter, the check valve in the bulb will keep the fuel from flowing backwards.

On the filter. The filter will fill up until the exit line is covered. On a cartridge filter laying on it's side, that's about half full. If it is inverted it will be less than that.

If the filter is right, and it is not filling to the exit line, then there is an air leak in the fuel line or pickup tube before the filter. Dip tubes in the tank are famous for this.

I'm running a screamin' v6 with the original pulse pump on the motor on this rig. Tank, Racor fuel filter/seperator, line, bulb, (skipped the bayonet) line into the oil mixer.

hope it helps
John

If the filter comes before the bulb, the the valve in the bulb will have no effect on the fuel being retained in the filter. The tank is a vented system and as long as air can displace the fuel, it will drain back into the tank. putting the filter after the bulb, the valve will stop the backflow...

j_martin · Oct 28, 2009

Re: Fuel line/filter Bulb question??

Knightgang said:
If the filter comes before the bulb, the the valve in the bulb will have no effect on the fuel being retained in the filter. The tank is a vented system and as long as air can displace the fuel, it will drain back into the tank. putting the filter after the bulb, the valve will stop the backflow...

So, a soda straw doesn't work?

j_martin · Oct 28, 2009

Re: Fuel line/filter Bulb question??

sschefer said:
John, are you still running oil injection on your XR. If so do you run a 5/16" inline filter between the fuel pump and first carb to catch any dirt that might get into the oil tank? I didn't for a long time until I had a problem with dirt in oil that I bought at Wally World. More my fault than anything. I didn't notice that the seal was broken.

No, but I am religious about oil quality and oil handling. Normal atmospheric dust is way too fine to stick in a carb, and I sure don't put oil in from an open container from Wally World, or anywhere else. When I crack a gallon of oil, it goes in, usually 3 at a time, and under carefully controlled conditions.

When I bypassed the bayonet, and the filter, I cleaned out everything and filtered the oil that was in it. There was a little chit in the oil, but that was from the PO.

Any time I break a fuel line, as in for maintenance, I cap off and plug everything.

I figure that if somehow a drop of water gets into the system and forms a bit of sludge, it'll plug that little lawn mower filter and starve the engine. (been there, done that) Odds are it would go through a carb with no ill effect.

Thanks for your concern.
John

hkeiner · Oct 28, 2009

Re: Fuel line/filter Bulb question??

So here's the question when I pump up the bulb I can see the fuel come through the filter but it never fills up only maybe a quater,when running its empty,I am thinking somewhere in this neighborhood is where my problem is.Not getting enough gas???? Any suggestions...

Fuel tank--fuel line-- filter-- fuel line-- bulb-- fuel line--Engine

You have already received lots of good advice but I'll add my two cents worth....Insert a short piece of clear hose inline at various points in the fuel line system, at one connection point at a time. Start at the tank and work your way towards the motor. Look for any air bubbles in the line while the motor is running. This systematic approach will show you where the air leak is, if there is one.

but it still seems to be not getting enough fuel

What makes you think it is not getting enough fuel? What are the symptoms when the motor is not running OK? Perhaps you have a fuel line restriction or ignition problem, rather than an air leak.

Gomer50 · Oct 28, 2009

Re: Fuel line/filter Bulb question??

I went through the whole fuel system and it is all new a works great.Its not running worth a darn.So I figured I would concentrate on timing/distributor etc. I looked at the distributor and saw the points pretty rusty looking so I took them out and noticed this isnt what its supposed to look like.Called the Marine shop (we have become pretty good buddies) and he said that motor shouldnt have points.By the way Its a 1972 Mercury 800.It should have a magnito.And he also said that was probably why I didnt have a switch box either.So I was advised if I wanted to run this motor I would have to invest,with the right distributor,switch box.Then I might get lucky and get this thing runing properly.Very disappointed at the person I bought this from and I guess at myself for not knowing better.Some things are just learned the hard way.Anyway thanks guy's for all the input..

sschefer · Oct 29, 2009

Re: Fuel line/filter Bulb question??

j_martin said:
No, but I am religious about oil quality and oil handling. Normal atmospheric dust is way too fine to stick in a carb, and I sure don't put oil in from an open container from Wally World, or anywhere else. When I crack a gallon of oil, it goes in, usually 3 at a time, and under carefully controlled conditions.

When I bypassed the bayonet, and the filter, I cleaned out everything and filtered the oil that was in it. There was a little chit in the oil, but that was from the PO.

Any time I break a fuel line, as in for maintenance, I cap off and plug everything.

I figure that if somehow a drop of water gets into the system and forms a bit of sludge, it'll plug that little lawn mower filter and starve the engine. (been there, done that) Odds are it would go through a carb with no ill effect.

Thanks for your concern.
John

I figured you would be one to be meticulous about your oil. I got side swiped at WW. That won't happen again.

You would have been shocked at the oil tank that I took off my 2.0L. Some people just don't understand that oil is designed to reduce wear and not for making slippery dirt.

sschefer · Oct 29, 2009

Re: Fuel line/filter Bulb question??

Gomer50 said:
I went through the whole fuel system and it is all new a works great.Its not running worth a darn.So I figured I would concentrate on timing/distributor etc. I looked at the distributor and saw the points pretty rusty looking so I took them out and noticed this isnt what its supposed to look like.Called the Marine shop (we have become pretty good buddies) and he said that motor shouldnt have points.By the way Its a 1972 Mercury 800.It should have a magnito.And he also said that was probably why I didnt have a switch box either.So I was advised if I wanted to run this motor I would have to invest,with the right distributor,switch box.Then I might get lucky and get this thing runing properly.Very disappointed at the person I bought this from and I guess at myself for not knowing better.Some things are just learned the hard way.Anyway thanks guy's for all the input..

Don't get all dissapointed just yet. Start another post with the new found problem and start watching eBay for the parts. Who know's someone here may have a better and cheaper solution. Lot's of good minds here to help you get things figured out

hkeiner · Oct 29, 2009

Re: Fuel line/filter Bulb question??

It seems unlikely that someone retrofited the motor with a differently designed ignition system than what came on the motor when it was built, i.e., addiing or removing ignition components. I would instead guess that you either have a motor that is a different year than what you think you have or the marine shop is mistaken. Your best bet, I think, is to troubleshoot/repair/replace any defective ignition components that are on your motor. A spark tester, DVA meter, multi-meter, and a shop manual for your motor will guide you in such troubleshooting. Just my thoughts...

Fuzzytbay · Oct 29, 2009

Re: Fuel line/filter Bulb question??

Its possible someone swapped out the powerhead, for an older one. Maybe you post a couple pics of what you have, that might help out getting some answers.

Gomer50 · Nov 2, 2009

1971 Merc Outboard Distributor question

1971 Merc Outboard Distributor question

I am looking to replace my distributor with another one,the one i am interested in purchasing is off a 1971 mercury outboard 650 4 cylinder.I looks just like mine that came off my 1971 merc 800.Can someone tell me if they are identical.THE Model 650, sr# 3000662 and mine is 3192883. Thank guy's I appreciate the help.

Fuel line/filter Bulb question??

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