Gelh 7800 Starter problems

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skiwest

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Feb 22, 2006
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I think I have this solved but it took most of the summer. Bougth my Gelh 7800 at an auction in the winter and didn't start using it till the spring. Died first day couldn't restart it. Brought in local diesel guy. Starter dead. Couldn't get a new starter so got rebuild. Rebuilt didn't last 8 starts. Comes out again but this time when we go back it hasn't been reinstalled . Rebuilt fell a part when they were trying to reinstall it.
At this point said thei is enough I'll get a new starter form dealer where we live. You guys install it and we're square. New Gehl starter was not the same as original and came with a new pipe to allow it to fit. Guy installed it but couldn't get it to start, eventually did but wouldn't restart after he left.
I had to take charge followed throught the start circuit , replaced some relays got it going. Though starter died again very quickly. Took it back to dealer and had it rebuilt for 25% of what the original diesel guy got. Feed back through dealer was that it failed on low voltage. Checked out battery at same time and was good. Reinstalled and doubled up on wire suppliing soleniod from the start relay. Got a fair number of starts on it but died again. But getting a lot better.
Went directly to rebuild shop for starter and learned a lot. I was on right track with doubleiing up on supply wire. (reason I doubled up was that there was a non original 3 wire cable from start relay to starter soleniod but was only using one of the wires, I just connected them with a crimp on fitting).
They said that problem was either the battery didn't have enough power or there was too much voltage drop in the circuit to the soleniod. The motor was fine it was the plunger on the soleniod which needed to be cleaned up due to arcing.
My fix. I had already increased the line from start realy to soleniod , rebuild guys said more than adequate for 60 amps the soleniod was pulling. However the supply line into the start relay came from the overall electral system and not direct from the battery like the starter motor gets its power. Also the line to the start realy was quite small , same as the other control wires #10.
So I disconnected that and ran a new wire from the post on the starter motor to the start relay using 6# wire. HAve had tons of starts on it now and so far trouble free operation.
I have a suspision that the construction company that had it before me just wasn't able to solve the problem. May have replaced wire from start relay to starter jsut to make repalcing the starter easier.
This seems like a design flaw in the wiring design.
 

Tazza

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I'm glad you have it all sorted out, you can never use cable that is too thick from the battery to the starter!.
The cable i used from my starter relay to the starter motor is still fairly small but works no problems.
Was the starter spinning slowly? Thats the only way i can see you can damage the starter motor.
 

skidsteer.ca

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Jan 20, 2006
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I'm glad you have it all sorted out, you can never use cable that is too thick from the battery to the starter!.
The cable i used from my starter relay to the starter motor is still fairly small but works no problems.
Was the starter spinning slowly? Thats the only way i can see you can damage the starter motor.
Your should put a voltage tester on he battery then crank the engine, see what your volts drop to.

see what your volts are at the batt then the starter, this will tell you how good your cables are.
Then check you batt at no load to see if you discharged t much, iy you no load volts drop more then .3 or .4 your batt may be too small
12.5= full batt no load, hopefully your volts return to 12.4 or so, after test
ideally the under load voltage at the start should be the same as the battery.
Ken
 

skiwest

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Feb 22, 2006
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20
Your should put a voltage tester on he battery then crank the engine, see what your volts drop to.

see what your volts are at the batt then the starter, this will tell you how good your cables are.
Then check you batt at no load to see if you discharged t much, iy you no load volts drop more then .3 or .4 your batt may be too small
12.5= full batt no load, hopefully your volts return to 12.4 or so, after test
ideally the under load voltage at the start should be the same as the battery.
Ken
Actaully the starter motor was never the problem with the last two rebuilds. It was only the starter soleniod. Not sure about the first one. It could have been the problem maybe way that is why it was so much more.
The cable changed was not from battery to starter motor but from the general power circuit to the starter soleniod.
The +ve circuit went battery to stater motor post with big cable. The starter post was used as terminal for rest of circuit. There were 3 lugs on that post, one for battery, one for battery boost and one to supply +ve to the rest of the system. It was a bugger to get all three lugs on as cables were short plus not very accesible.
What the problem was the starter relay was feet of wire ( voltage drop) away from the battery. And it had a significant amp draw. So by the time it got to the starter soleniod the voltage was too low to hold in the soleniod plunger against the spring force.
So waht I did was cut out the middle men so to speak but powering the start relay power side directly from the battery using big cables.
 

skiwest

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Feb 22, 2006
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Actaully the starter motor was never the problem with the last two rebuilds. It was only the starter soleniod. Not sure about the first one. It could have been the problem maybe way that is why it was so much more.
The cable changed was not from battery to starter motor but from the general power circuit to the starter soleniod.
The +ve circuit went battery to stater motor post with big cable. The starter post was used as terminal for rest of circuit. There were 3 lugs on that post, one for battery, one for battery boost and one to supply +ve to the rest of the system. It was a bugger to get all three lugs on as cables were short plus not very accesible.
What the problem was the starter relay was feet of wire ( voltage drop) away from the battery. And it had a significant amp draw. So by the time it got to the starter soleniod the voltage was too low to hold in the soleniod plunger against the spring force.
So waht I did was cut out the middle men so to speak but powering the start relay power side directly from the battery using big cables.
Just to add that my starter had a post for the motor and a seperate post for the soleniod. The starter motor was a 3KW which might be bigger than most skid steers as the engine is 110 hp.
 

mustang2105

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Nov 5, 2006
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Just to add that my starter had a post for the motor and a seperate post for the soleniod. The starter motor was a 3KW which might be bigger than most skid steers as the engine is 110 hp.
Never heard of so many problems like your having. I have a 2105 and i was surprised on how tiny in size the starter is. The cables travel pretty far also going all the way to the front of the cab.
 

skiwest

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Feb 22, 2006
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Never heard of so many problems like your having. I have a 2105 and i was surprised on how tiny in size the starter is. The cables travel pretty far also going all the way to the front of the cab.
The 7800 is “same “ as the 2105 but has different engine so different starter. The first starter was a Hitachi which I guess went out of production so Gehl changed to a Denso. Both are 3kw.
Starter didn't seem so small when trying to install , hold up with one hand and get the bolts in the the other with not enough room for two arms. Mechanic took 3 hours getting in new pipe spool and starter. Second time I did it went a lot faster after I make up some install studs.
Installed studs ( metric bolt with head taken off and a notch for a screw driver) , then installed starter, then switched out studs one at a time for bolts.
 

mustang2105

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Nov 5, 2006
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The 7800 is “same “ as the 2105 but has different engine so different starter. The first starter was a Hitachi which I guess went out of production so Gehl changed to a Denso. Both are 3kw.
Starter didn't seem so small when trying to install , hold up with one hand and get the bolts in the the other with not enough room for two arms. Mechanic took 3 hours getting in new pipe spool and starter. Second time I did it went a lot faster after I make up some install studs.
Installed studs ( metric bolt with head taken off and a notch for a screw driver) , then installed starter, then switched out studs one at a time for bolts.
I thought the engines were the same Yanmar 4tne-106
 

2109 Stang

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Nov 8, 2006
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I must be wrong , I thought that the Mustang had a perkins.
The 2105 started with the yanmar ,when they change to 2109 it had a perkins but I think it was only for a year or two till 2005 witch is what I have on mine and 2006 they put a cummins with 100hp the perkins has 115 hp and the yanmar 110hp.
 

2109 Stang

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Nov 8, 2006
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The 2105 started with the yanmar ,when they change to 2109 it had a perkins but I think it was only for a year or two till 2005 witch is what I have on mine and 2006 they put a cummins with 100hp the perkins has 115 hp and the yanmar 110hp.
I fail to mention that the 7800 is the exact machine as the mustang everytime there is a change it goes for both actually they make one machine with different decals .
 

skidsteer.ca

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Jan 20, 2006
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It has ran well all winter. Now I just a a problem with priming the engine after changing the fuel filter.

The wiring change seemed to do the trick.
You can't put a outboard primer bulb in the fuel line to act as a manual lift pump?
Ken
 

skiwest

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Feb 22, 2006
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You can't put a outboard primer bulb in the fuel line to act as a manual lift pump?
Ken
The one on the side of the injector pump? Found that. Loosen and then pump uppand down? Didn't seem to do trick. The operators manuls talks about a bleed valve and a lever pump . But the service manuals or parts doesn't show it.
 

skidsteer.ca

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The one on the side of the injector pump? Found that. Loosen and then pump uppand down? Didn't seem to do trick. The operators manuls talks about a bleed valve and a lever pump . But the service manuals or parts doesn't show it.
There should be a screw or valce to vent the air out on the pump or fuel filter someplace to, or else loosen the the filter then use the hand pump.
Ken
 

skiwest

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Feb 22, 2006
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There should be a screw or valce to vent the air out on the pump or fuel filter someplace to, or else loosen the the filter then use the hand pump.
Ken
Spoke to Gehl and that seems to be the way to do it. I had the pump just needed to find bleed screw. They also suggested starting will a full fuel tank would assit and loosening the fuel filter would also do it.
 

skiwest

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Feb 22, 2006
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Spoke to Gehl and that seems to be the way to do it. I had the pump just needed to find bleed screw. They also suggested starting will a full fuel tank would assit and loosening the fuel filter would also do it.
Problem was that previous owner had installed a elec fuel pump and bypassed the fuel pump on the injector pump. This electric pump was mounted high. So had to take off mounting bracket so pump had flooded suction , run pump off of 12 v, then remount and then start. Now everything working, digging holes for piers and digging up stumps.
 

mustang2105

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Nov 5, 2006
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Problem was that previous owner had installed a elec fuel pump and bypassed the fuel pump on the injector pump. This electric pump was mounted high. So had to take off mounting bracket so pump had flooded suction , run pump off of 12 v, then remount and then start. Now everything working, digging holes for piers and digging up stumps.
Hello Skiwest. I think i'm having the same problems as you with the starter. Where is the relay located. I think my battery maybe shot. Do i have to take all those plastic pieces off to get to battery? lOOks like a pain in ass. Thank You
 
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