Geoff Z
Hey Guys,
I've got one for Ziller to put out there for our brain trust. We have 2 older Nissan ForkLifts: Both ForkLifts have the same Nissan 4 cylinder propane engine. They both turn over poorly and have done the same thing for years. Always bothered me and I though why not ask our guys to see if there is any input.

We keep good batteries in them. Both have on board functioning alternators. We have wired in Generac 0G8023 chargers and they stay plugged in when units are parked. During crank we stay about 10.4v. First start in the morning we may get 4-5 seconds of good crank, then dump down to almost not cranking at all. Even when it will almost not turn the battery holds solid at 10.4. When the crank speed dumps down we only hold the key 3-4 seconds with rest in between. For fear of burning up the starter due to extra heat. Usually 2-4 crank cycles they start right up. They always start every time. The rest of the day once they have been warmed up they will start 1-2 crank cycles. We are on and off them constantly. Normally a lot of short runs daily unless we are unloading a semi or something they can get an extended run. At least 1 or 2 times per day they will intermittently turn over like a scared rabbit. Just baffled?? thx Geoff   
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murphy
Are you measuring the voltage during crank at the battery or the starter motor?  If the battery, measure at the starter motor.  If a lot lower investigate the battery cables, especially the ground connection at the starter.
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Geoff Z
Measured at battery. That makes sense to measure at the starter. It will take a contortionist to get to it! Both forklifts are about the same age. So I guess it could be realistic they both have cable issues. However they both have acted that way for 10+ years. I just finally figured why put up with it anymore if we can kick it around here and come up with a solution. I'll report back on starter measurements. thx
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Cobranut
Agree with Murphy.
Check the entire path from battery +, through any starter relay, to the starter, and also check for voltage drop between the starter case itself and the battery - terminal. 
Any drop of more than a volt or so can be a problem. 

Once you narrow it down, use an infrared thermometer to find any warm connections or cables right after cranking in the morning when everything is cool.
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78buckshot
Hey Geoff, when they do fire up do they blow black smoke or can you smell overly rich exhaust? Do you shut the tank valve off at the end of the day to keep from loosing propane? Way back in my prior life and even today I have seen several LP lift trucks with leaks that would give just a whiff of propane when the machine was not in use. You could run a test and it won't cost anything other than some memory cells, turn the valves off tight after the last use of the day and in the morning as you get ready to use them turn on the gas and see if it changes the behavior.
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Geoff Z
No black smoke but yes rich smelling exhaust. We have never shut the valves off at night. In fact one of the units is more of a back up role. It can sit for a few weeks with the valve open. In spite of the labored crank it will always start faithfully after a long down time.  Neither unit has a fuel smell when sitting static. I will be giving that a try. 
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78buckshot
My other thought is from your first description, if the batteries are always on a charge and the cables check out good then I would suspect the starter motor, could be worn brushes or the shaft bushings or the windings. Have you done a load test on the batteries other than the voltage staying constant while cranking?
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Birken Vogt
Don't count out a bad starter motor.  Suffered through that for many a year on an old truck and fork lift, finally repaired them and the difference was night and day.  Fools you into thinking bad battery, cables, etc.
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Geoff Z
We have not done a load test. The every day unit has a new battery. I don’t remember the age of the battery in the back up unit. The starter in one of the units had to be replaced some years ago. I don’t remember if that unit cranked better with the new starter? Bad memory...
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Geoff Z
Update: buckshot's post about shutting off the propane tank made some sense to us. One of my partners has said for a long time now that this feels like compression not allowing the crank rather than electrical. We just didn't understand how. Also some of the very first cranks of the day were terrible when we knew it had overnight rest. So yesterday while running we shut the propane valve off and allowed it to run out of fuel and stall. Immediately put about 6 cranks on it with fuel valve closed. All cranks were perfect. We then opened the valve. The rest of the day we got more good cranks then labored cranks. So it wasn't perfect but much better. Left the valve closed over night. Today I've started it maybe 12 times. We jump on and off the fork truck all day long.  All good cranks but 3. So we have exhausted our abilities in this area. We did some good though. We eliminated the electrical as the problem. We helped it crank somewhat better. Hopefully this will help starter life without so many labored cranks. So unless somebody has anything else we should consider, knowing us we will stay where we are at for now. Fork truck repair folks are way more proud of themselves than electricians! Their fees reflect that...Thanks guys for the ideas.
 
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78buckshot
So if my HVAC and generator career goes belly up I can come work on your forklifts?
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Geoff Z
78buckshot wrote:
So if my HVAC and generator career goes belly up I can come work on your forklifts?


Sounds like a good plan!
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fixer5000
have you removed and cleaned or replaced the inline fuel filters?? years ago company i worked for had an issue with rust in the gas bottles and that made for hard to start issues. they are small sintered bronze type filters in a block between the tank and engine
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Geoff Z
We have not. The tanks are swapped from the supplier. We must have 6-7 tanks. I suppose we could have gotten some with rust over the years. It never acts like fuel. If we get a good crank both units will start right up. We have gotten more good cranks from both units now that we are shutting the fuel down overnight. Not a miracle but somewhat better. Enough to make me feel more confident we won't burn up the starters.
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restosud
Geoff Z wrote:
. Fork truck repair folks are way more proud of themselves than electricians! Their fees reflect that...Thanks guys for the ideas.
 

As opposed to many many gen tech companies out there? hmmm....

don't know how old your lifts are but starters are considered a wear item as they cycle a lot. you could open one up and clean all the carbon and trash out and perhaps a minor overhaul.you'l be surprised at how much junk is in there!
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Geoff Z
restosud wrote:

As opposed to many many gen tech companies out there? hmmm....

don't know how old your lifts are but starters are considered a wear item as they cycle a lot. you could open one up and clean all the carbon and trash out and perhaps a minor overhaul.you'l be surprised at how much junk is in there!


Here in Michigan we have a lot of competition. At both generators and electrical contracting. Some of it very reputable. We are working very modestly here.

Yes of course starters are a normal wear item. They are absolutely impossible to get to. So I'm certain they will never get any care. Just replacement if they puke. The one we replaced years ago was done by a contractor. Shame on us, someone should have paid attention from a safety perspective. It has to be done from underneath. Just an irrational fear of putting an arm under that thing even with jacks, stands, and blocks.

On a positive note shutting off the fuel valves each night has helped a lot. Not perfect but much better.
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