fuel pump or lack thereof

shortcut · June 11, 2013, 05:29:41 PM

from what I read, 89 was the year of introduction of a fuel pump on a 1200. Why is a pump necessary when the fuel is a minimum of 5 inches above the float bowls. My circuit is good to the pump for a few seconds when ign is turned on. The pump appears to be bad (shorted) when tested on an outside source. My manual shows a vacuum petcock but the one on the bike is a on / off quarter turn that no human could reach to turn if it had a lever, which it doesn't. On the left side of the fairing by the choke is a electrical rocker switch that is marked RESERVE. How could running the pump help if the tank was empty. The pump has 1 source, the quarter turn petcock, the petcock has single hole to admit fuel from the tank, with no screen tube on it. 5/16 fuel line to filter, under the tank, reduced down to 1/4 out of filter then down to mid right side to pump. 1/4 out of pump back up and across under carbs to left side to fuel manifold line tee. I'm not Ronnie Racer and can't see why this wouldn't get me down the road with a short, left side 5/16 line from petcock to fuel manifold line. HELPPP. These pumps are expensive!!!

movenon · June 11, 2013, 05:50:52 PM

First, a lot of times it is the points that fail in the pump. There is a replacement/rebuild kit if that's what it is. RPM stocks them.
http://www.rpmracingca.com/proddetail.asp?prod=M%2FC%3AF%2FPPointSet&cat=34

Now as to gravity feed. The Fuel pump models have an external filter that is real restrictive in a gravity feed mode. You need to run a line from the petcock to your carbs. Be aware that in the fuel pump models the needle and seat valve in the carbs are about 50% smaller in diameter.

Also now if you are feeding directly from the tank the only thing stopping fuel from flooding uncontrollably into your carb and engine is the needle and seats....
I believe the stock fuel pump has a shut off / check valve built in to prevent fuel from flowing when the engine is off. That's only a belief. I haven't tested that.
There other fuel pumps that you can adapt if you needed to. Check the points in the pump you have first.
George

fj11.5 · June 11, 2013, 05:55:05 PM

The pump is supposed to shut off 5/7 seconds after the ignition is switched on, so the carbs are primed, then the pump starts again once the bike starts up, at least it should anyway

jscgdunn · June 11, 2013, 06:22:50 PM

Randy has this aftermarket pump:

http://www.rpmracingca.com/proddetail.asp?prod=fuelsystem%3AFP&cat=39

We do carry a spare on long trips. Simpler than modifying I think. The early model petcocks cost more along with changing needle/seat etc., fuel lines, ....

Jeff

shortcut · June 11, 2013, 06:54:29 PM

I checked and there is some kind of a weak check in the pump that can be overcome with slight pressure, about as much as it takes to start inflating a small balloon. I filed the points (I didn't know there were any until I took the end cap loose on the pump). Pump works good now BUT, does this pump have to run all the time when the motor is running or does it have some kind of a pressure cut out switch?

fj11.5 · June 11, 2013, 07:00:11 PM

pump runs to keep the carbs full , while engine is running ,

ribbert · June 11, 2013, 07:48:20 PM

Quote from: shortcut on June 11, 2013, 06:54:29 PM
BUT, does this pump have to run all the time when the motor is running or does it have some kind of a pressure cut out switch?

Yes it does but not at the rate you hear when you first turn it on, it self regulates to only supply fuel as required, which is probably a tick every second or so when cruising.

ribbert · June 11, 2013, 08:19:36 PM

Gravity feed fuel on the early bikes is a common topic here. The head pressure of the fuel only being a few inches above the carbs is not very high and does not take much to stop it. Tank venting, fuel line routing, petcocks and carbs can all cause an interuption to fuel flow. It also doesn't allow for a decent in line filter. Petcocks themselves are also a common maintenance item.

A fuel pump gives a far more reliable fuel feed and it is reasonable that you would expect to replace it perhaps once in the life of the bike.

The petcock you refer to on the tank outlet is not intended for regular use but to shut the fuel of if removing the tank or disconnecting the fuel lines or fuel pump.

As fj11.5 says it will only run for a set amount of time when the ignition is first turned on then stop, until you start the motor.

BTW, I run a $25 ebay pump on FJ#2. Not sure I'd head off around the country with it but it works fine. Any low pressure pump will work., however, what you pay for it will probably give you some idea of its life expectancy.
Do you have a problem with your pump or is it just academic interest?

Noel

shortcut · June 12, 2013, 01:14:31 PM

I think I'll try the "no pump , no filter, option around home and if it is not satisfactory, I'll hook up the original pump that I filed the points on. It seems to function fine on the bench. I will reply back after testing.
Thanks, Mike

movenon · June 12, 2013, 06:08:41 PM

Quote from: shortcut on June 12, 2013, 01:14:31 PM
I think I'll try the "no pump , no filter, option around home and if it is not satisfactory, I'll hook up the original pump that I filed the points on. It seems to function fine on the bench. I will reply back after testing.
Thanks, Mike

I would not advise you to do what you are suggesting as anything but get home fix?..... These things will catch on fire.... If it leaks fuel past the needle and seat (very likely) it will dump all the fuel in your tank on the floor and also fill your engine crankcase with fuel.
I can not recommend strongly enough that you put your pump back in place.....
If you park your bike in a garage you risk a fire...........
George's opinion

Pat Conlon · June 12, 2013, 07:33:56 PM

Mike, listen to George.

If you do need a new pump, you don't have to buy a FJ fuel pump ($$) there are other alternatives available to you which are less costly. Check out the Files section.

Put your pump back in.

shortcut · June 16, 2013, 02:24:42 PM

You got my attention with the fire note. I put the old pump with the filed points back in with the small inline filter attached up under the tank. Runs good now. Just ordered a AIRTEX E 8016 S pump from car quest (pressure specs the same as stock). Somewhat longer overall but should clear easy enough with added filter that is supplied but 1 filter on inlet line should be enough so 2nd filter can be omitted which shortens OA by 1 1/2". I figure this will be easy enough to carry as a spare and change out if original fails. Thanks for the heads up and coaching.
Mike

1wormsway · July 14, 2013, 04:53:34 PM

Quote from: shortcut on June 16, 2013, 02:24:42 PM
You got my attention with the fire note. I put the old pump with the filed points back in with the small inline filter attached up under the tank. Runs good now. Just ordered a AIRTEX E 8016 S pump from car quest (pressure specs the same as stock). Somewhat longer overall but should clear easy enough with added filter that is supplied but 1 filter on inlet line should be enough so 2nd filter can be omitted which shortens OA by 1 1/2". I figure this will be easy enough to carry as a spare and change out if original fails. Thanks for the heads up and coaching.
Mike
Good day all, I am on my 4th Fj and have stripped the fuel pump off every one and garbaged them. Funny thing is that I have never been stranded due to pump failure. YAMAHA HA HA HA !!!

1wormsway · July 14, 2013, 05:03:42 PM

New at this posting thing and new to site / newbie. So I will try again to post this without the previous quote attached:

Good day all, I am on my 4th Fj and have stripped the fuel pump off every one and garbaged them. Funny thing is that I have never been stranded due to pump failure. YAMAHA HA HA HA !!!

1wormsway · July 14, 2013, 05:13:14 PM

In response to MOVENON' s " Fire Risk" I would have to ask how fuel would leak passed the needle and seat just baecause there is no fuel pump. The pump is designed to pump fuel and in no way holds it back. If needle and seat are bad you have a potential Fire Risk but removal of pump in no way puts you in this category.

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fuel pump or lack thereof