How to remove old bad gas from EFI gas tank?
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From: Kansas City, Missouri
How to remove old bad gas from EFI gas tank?
I just bought a 1999 Road king Classic thats been sitting for a while. When it was first started it would not idle and would die. The tanks was kinda low so added fresh gas and some sea foam with it. Got it to idle and got to ride it around some it runs put spits and sputters. It acts like it wants to run ok - I can get it to run smooth but I reach a certain RPM and it starts cutting out and you have to shift to a higher gear to keep moving ok. I finally got it running good enough to get on the hiway and it ran up to 80MPH but it isn't right. Once I used a 1/2 tank it started running really rough again so I want to start by dumping the fuel in the tank and flush the tank out. I'm unsure how to do this on a EFI bike. Can't you pull the fuel line and wire the fuel pump to pump all the gas out of the tank? I haven't got a service manual yet and want to try and do it before it gets really cold and I have to park it for the winter. Any suggestions?
Thanks for any help in advance and HAPPY Thanksgiving. Rick
Thanks for any help in advance and HAPPY Thanksgiving. Rick
Intermediate
Joined: Mar 2010
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From: erie, pa
crossover tube, front of the tanks on the bottom, use needle nose pliers with rubber tube over the jaws to pinch off one side then pull hose off of the other, be ready with another piece of hose to put on the side you pulled off, make sure its long enough to drain into a gas can.
Tourer
Joined: Nov 2011
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From: USA
I keep an outboard motor squeeze ball primer with gas line attached to each end for just that purpose. A couple of feet of hose on the input side (to go into the tank), and a few feet on the output side to go to a gas can. Use the primer to start the siphon, then just let it siphon out. You can use the squeeze primer to suck the last bit of gas from the lowest spot in the tank.
HDF Community Team
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From: san antonio
Any of the above but the tank. If the bike is carbed, I would pull everything off from the petcock to and including the carburetor. You could have crud anywhere between the tank and the intake. When you pull the petcock, open remove the fuel tank cap and every drop will drain out.
If the bike is fuel injected, I would do the same thing, the difference being you are dealing wtih throttle body, IAC port and injectors.
I would also start with a fresh set of spark plugs and check for intake leaks if it has been sitting for quite a while, intake seals could be leaking.
I missed that this was an EFI bike; forget the carbed comments. im's suggestion to check the internal fuel supply line for a pinhole is a good suggestion as well. But if that is the problem you should be able to hear the pressure leak.
If the bike is fuel injected, I would do the same thing, the difference being you are dealing wtih throttle body, IAC port and injectors.
I would also start with a fresh set of spark plugs and check for intake leaks if it has been sitting for quite a while, intake seals could be leaking.
I missed that this was an EFI bike; forget the carbed comments. im's suggestion to check the internal fuel supply line for a pinhole is a good suggestion as well. But if that is the problem you should be able to hear the pressure leak.
Last edited by djl; Nov 25, 2011 at 12:36 AM.
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From:
If this is a 1999 road king classic? consider possibility of the INTERNAL fuel line inside tank having a rub mark hole. The hole causes the inability to maintain fuel pressure when tank is below 3/4 and gets worse as it goes below the fuel line level. Look for bubbles in gas tank...look thru gas cap hole while it primes...also review fuel lines because if you have the two fuel line deal under the tank then the lines could be old and have a leak..kinda like sucking thru a straw with a hole which then causes low fuel pressure and the inability to pick-up speed and it just bogs down due to not enough fuel..good move on clearing out fuel first.
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Seasoned HDF Member
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From: Kansas City, Missouri
Good ideas everybody. It is a 99 RKC with MM EFI. I think it has the 2 hose under the tank as described.It looks like somebody add a external fuel filter under the tank. That may be clogged up also. I'm going to try and work on it today as its our last warm day for awhile. I at least want to try and remove the sour gas in the tank, so if I have to store it it will be with fresh gas. I'll post back on how it works. Thanks everyone. Rick
Last edited by heavymetalthunder; Nov 25, 2011 at 10:26 AM.
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HDF Community Team
Joined: Jun 2006
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From: san antonio
Good ideas everybody. It is a 99 RKC with MM EFI. I think it has the 2 hose under the tank as described.It looks like somebody add a external fuel filter under the tank. That may be clogged up also. I'm going to try and work on it today as its our last warm day for awhile. I at least want to try and remove the sour gas in the tank, so if I have to store it it will be with fresh gas. I'll post back on how it works. Thanks everyone. Rick
Add a fuel stabilizer that is specific for ethanol "contaminated" fuel to the fresh fuel if the bike is going into a dormant phase for the winter and put the batter on a tender. Don't bother to change the oil as it will collect moisture during storage. Just change oil and filter when you take her out of storage next season.
BTW, the MM EFI system had many problems which is why it was replace after two years with the Delphi system. At some point in the future you might want to conver to carb.
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Seasoned HDF Member
Joined: Jan 2008
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From: Kansas City, Missouri
Well I Tried siphoning the gas out with a squeeze ball primer with gas line attached to each end but didn't have any luck. Then I pulled one of the gas lines on the bottom of the tank. I go lots of fuel out but there was still enough left in the bottom to see. I filled with fresh gas and changed the plugs. Still runs the same. with a full tank or almost empty. I'll order a service manual and next spring redrain the tank and pull it off the bike and flush it out with fresh gas and see what happens. Thanks for all the replies. Rick
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