| Author | Message | ||
| harry edwards (Harry)
Registered Member Username: Harry Post Number: 1 Registered: 11-2006 Posted From: 72.0.44.104 Rating: N/A |
1957 GM 4104 - starts easily - runs for about 7 minutes then stops - must wait about 1/2 hour before it will start again - then repeats runs for about 7 minutes then stops What do you think is the problem? | ||
| Bob greenwood (Bob_greenwood)
Registered Member Username: Bob_greenwood Post Number: 352 Registered: 7-2006 Posted From: 4.90.6.104 Rating: N/A |
fuel filters | ||
| Geoff (Geoff)
Registered Member Username: Geoff Post Number: 902 Registered: 12-2002 Posted From: 71.211.118.136 Rating: |
I have dealt with this problem before, and the cause both times was crap in the fuel tank-- the engine will start and as it runs the pick-up tube becomes clogged and the engine cannot suction the fuel. After you let it sit for a while the suction lets off, the crap that is floating in the tank falls off the pick-up tube, and it will run again for a few minutes until the process repeats itself. It could be algea or it could be that someone threw a piece of paper in the tank. Hook your fuel draw up to a 5 gallon container of fuel (by-passing the fuel tank) and see if it stil does it-- if this fixes the problem, you will need to clean your fuel tank. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1110 Registered: 12-2000 Posted From: 67.181.163.170 Rating: N/A |
Harry - In addition to what Bob & Geoff mentioned, it's also possible that the "run - stop" Skinner valve on the firewall has failed. Does it start to build up air pressure, then when it gets to around 60 psi the engine dies? If so, that's indicative of either a bad Skinner valve, or a malfunctioning "run - stop" slave cylinder on the engine. FWIW & HTH. . .  (Message edited by rjlong on November 17, 2006) | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1742 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
I had this same problem when I first got my 4104 many years ago. I ended up putting an air hose to the fuel outlet line and blowing back into the fuel tank. I really never knew what it actually did, but it solved the problem. Richard | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 349 Registered: 10-2004 Posted From: 70.202.251.129 Rating: N/A |
Richard, maybe the generator sucked it dry? aCE | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 232 Registered: 11-2005 Posted From: 63.97.117.53 Rating: N/A |
Harry, In addition to what RJ said, on a 4104 there is a switch for mechanics to use to cut off the engine from the rear. If this is accidentally bumped it will do just as he said. It is easy to bump off when starting the engine from the rear. Don't ask me how I know this! There are four switches there. One to take the starter out of the circuit so it can't accidentally be started, one to start the engine, one to shut off the engine and one for the compartment light. These are located high on the right side of the engine compartment. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 233 Registered: 11-2005 Posted From: 63.97.117.53 Rating: N/A |
Usually when the fuel filter is dirty, unless it is completely clogged, the engine will run forever at idle but will stop when under load. | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1744 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
Ace, different bus. That problem was with my 4104 that had a separate fuel tank and the genset was gasoline, not diesel. I hated having to get diesel and then go to another pump to get gasoline. Richard | ||
| harry edwards (Harry)
Registered Member Username: Harry Post Number: 2 Registered: 11-2006 Posted From: 72.0.44.104 Rating: N/A |
Thanks everyone for the good answers. I will go through each solution and follow up with the results. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 236 Registered: 11-2005 Posted From: 63.97.117.19 Rating: N/A |
Richard, Most places I fuel have gas and diesel pumps at the same place. I like having the separate tanks and gas generators are far cheaper than diesel. My Honda water cooled gen is just quiet as any diesel. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 237 Registered: 11-2005 Posted From: 63.97.117.19 Rating: N/A |
Harry, Be sure to let us know what you find out - the rest of us 4104 owners can use the information. | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1751 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
I always fuel with the big boys at the truck stops and they never have gasoline there. Richard | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 239 Registered: 11-2005 Posted From: 63.97.117.36 Rating: N/A |
Richard, I learned quite a while ago that the auto pumps are much better. Diesel at auto pumps is cheaper in many places than at truck pumps - go figure, but it's true. Another thing is that the ground is much cleaner and in better shape - truck pumps are usually a mess. I use to drive an 18 wheeler and I always hated those places. Another thing I hate at truck pumps is having to use satellite pumps and going back and forth between two pumps, a real pain. I can't think of one good reason to use truck pumps except that access may be easier! | ||
| harry edwards (Harry)
Registered Member Username: Harry Post Number: 3 Registered: 11-2006 Posted From: 72.0.44.104 Rating: N/A |
To all who offered helpful information; many thanks. Problem has been solved. Turned out to be fuel was too low. Bus was parked on a slight grade - tilted about 4 to 6 inches lower on the passenger side. Engine would run and air up to about 60 lbs. - fuel level would drop to just below the pickup - engine would stop. Wait about 1/2 hour- fuel would drain back to tank and engine would start again. Added 50 gallons to tank - problem went away. So I learned - don't park on a tilted area with too little fuel. | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1753 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
I am surprised that the fuel pump re-primed the system. Typically when you run out of fuel, you havea major problem in re-priming the system. Richard | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 354 Registered: 10-2004 Posted From: 75.200.5.151 Rating: N/A |
Well that just goes to show you Richard, you don't know everything! | ||
| Richard Bowyer (Drivingmisslazy)
Registered Member Username: Drivingmisslazy Post Number: 1754 Registered: 1-2001 Posted From: 75.108.82.163 Rating: N/A |
I do not ever remember saying so. Richard | ||
| Frank Allen (Frank66)
Registered Member Username: Frank66 Post Number: 37 Registered: 10-2005 Posted From: 152.163.100.138 Rating: N/A |
here we go again with all the slurs, Why?? same thing with the mak board Frank Allen 4106 | ||
| H3-40 (Ace)
Registered Member Username: Ace Post Number: 355 Registered: 10-2004 Posted From: 75.200.5.151 Rating: N/A |
No slurs Frank, here or THERE! I'm just not the type to talk behind your back like SOME and candy coat the facts! If you can't handle the truth, oh well! You have a problem then! I'm not what you call "two faced"! I tell it like I see it and some people who you think are one way, tend to actually be another! Let's just say from now on I'm gonna change my ways when it comes to so called friends! Ace | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 241 Registered: 11-2005 Posted From: 63.97.117.35 Rating: N/A |
Harry, I'm really glad you kept it running but don't think the problem was solved just by more fuel because; There is no way fuel can drain back into the tank unless there is a small hole in the supply line or at a connection which lets air into the supply line and releases the vacumn in the line. If this happens the engine will lose prime and you will never get it to start. I've been through this drill - it is no fun. Even if the supply line drained all its fuel into the tank it would not be enough to raise the fuel level enough to restart. Same for the fuel return line, there just isn't much fuel in these small lines. This is only my opinion of course, but I think there was another cause other than just low fuel. I've been through this whole routine with my 4104 and got quite an education in the process! As Richard has said, it would never reprime once the supply line was empty or even if it only had a small amount of air in it. Once the supply line has air in it you are out of luck because this fuel pump is on the engine and is a suction pump, it does not push fuel from the tank. Do you know how much fuel was in the tank when you had this problem? My guess is that the fuel was contaminated and 50 gal of fresh fuel diluted the contamination. Water could have caused your exact problem. If you have the original primary fuel filter open the drain valve at the bottom while the engine is running and check for water or crud. It probably is so full of crud it won't even drain. Don't ask me how I know this either! A tip; always run the engine at about 1/4 - 1/3 throttle just as soon as it starts. This is not my idea, the GMC Operating Manual says 1/3, but that seems fast to me so I do it a bit slower. Just don't let it sit and idle. | ||
| harry edwards (Harry)
Registered Member Username: Harry Post Number: 4 Registered: 11-2006 Posted From: 72.0.44.104 Rating: N/A |
Thanks for additional possibilities. I don't know all the answers either. The last fuel was obtained from a local quick stop-and was down to about 20 gallons; when bus was parked. Had not started the bus in 6 to 8 months. Mayby water was in the tank and adding more fuel solved it. | ||
| Frank Allen (Frank66)
Registered Member Username: Frank66 Post Number: 39 Registered: 10-2005 Posted From: 207.200.116.13 Rating: N/A |
Ace, thanks for putting me straight Frank Allen |
