Here's the background story-
At my work we have a '73 Clark 6000 lb capacity forklift. I'm kinda the "do everything" guy here so forklift operation and maintenance both fall under my jurisdiction, so to speak. The forklift is powered by a gas Continental flathead straight six. We've had this forklift for a little over a year, and it really has not run correctly since we bought it.
Toward the end of last summer, I was running the forklift for an hour or two moving some stuff. The gas gauge on it isn't hooked up, so I didn't know what my fuel level was. It ran fine (well, as fine as it could, it's had some issues since we bought it) until I parked it.
A few days later I went to use it and it started, sputtered and died. Subsequent attempts to start it also failed. I opened the side cover and the fuel filter was full of rusty sediment from the tank, apparently the gas was low. (The forklift sat for awhile before we bought it so it had some crud in the tank. There is no provision to drain the tank on this thing so I haven't been able to do anything about it)
I changed out the fuel filter and added more gas- no go. We called out a service technician from a local forklift place and he said the fuel pump was dead, so I got a Carter P60504 inline electric fuel pump for it, and a holley 12804 regulator. Got all these installed, the pump works great and seems to move plenty of fuel, but still no start.
So, last week I pulled the carb off (Zenith 1 barrel updraft) and ordered a "repair" kit for it. To my dismay I found out the "repair" kit did not include any jets...only a needle & seat, gaskets, and a new idle screw. At any rate I tore the carb down...it had a little rusty sediment in the bowl but otherwise looked pretty good. I soaked it overnight in carb cleaner, blew out all the passages with carb cleaner, adjusted the floats, replaced the needle & seat, checked out all the jets, put it back together and put in the new idle screw.
I installed it a few days ago and attempted to fire up the forklift again. Well, now it would least idle (which it would not before) but it would still not run properly. The idle is low and adjusting the idle screw seems to have little to no impact on the idle speed, except that if you run the idle screw all the way in it'll shut off. The throttle is also very slow to respond. The exhaust smells like gas.
I should add that the spark plugs and wires are fairly new as I replaced them last year and we don't use the forklift too often. I have a new points and condenser but have not replaced them yet because the old ones looked pretty good.
Also- I installed a pressure gauge on the regulator. I currently have the regulator wide open because I found conflicting specs on the pump, but I don't know for sure yet. However I never get any sort of a pressure reading on the gauge. Any ideas there? Should I just take the regulator off? Supposedly the pump does 4-7 psi.
I tried to start it yesterday and while it would start, it was idling extremely low, just going "chug chug chug"...sounded like an old steam locomotive. This is similar to what it was doing before. If you tried to give it throttle it would start to rev up slowly, then choke out and die.
Thanks for any help- I really don't know what the deal is with this thing. I figured cleaning out the carb would fix it but it hasn't.
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That's right, he did. and this is the second time ive responded with a technical answer. Ive also offered to help him out in private e-mail if things get too hot in here, _again_...
if that isnt to his satisfaction im sure he will let me know.
Do you disagree that the importance of safety isnt worth underscoring here especially as/re a forklift this old? Because discouraging safety warnings isnt helping anybody.
i dont know how tightly forklifts are regulated in the US but up here an operator's license is mandatory, an annual lifting device inspection is also mandatory, and anyone performing maintenance and repairs to a forklift has the burden to prove they are qualified to do so... failing that in a ministry of labour investigation carries a very stiff penalty---enough to bankrupt most of us.
not to mention the damage that truck can do if it breaks...
What's with the arms getting cut off, forks going through chests, and your life will be ruined? He's the maintenance guy at work and he asked how to make his forklift stop running rough.
garrett, the carburetor has some lingering issues. i would suggest sending it out to be rebuilt.
it's possible this carburetor is not calibrated correctly for the engine application---it could just be a used carburetor some fly-by-nighter threw on it so they could flip it. so just exchanging it for a reman is not your best approach---you will just get an identical carburetor in return.
i would start with your local clark dealer. believe it or not parts and information are still available as there are many c500s still in daily service.
there are a number of other things you should be testing here, which i outlined in an earlier post that was clipped, but as i said then, this is all way beyond the scope of a forklift operator and because this truck is being used at your workplace, you can be held personally liable if this truck fails and causes an accident while under your care. If one of your co-workers loses an arm because a fork or chain snapped, if the brakes fail and you put it through a wall and into someone's chest, you get sued---or worse yet, youre the victim yourself---get the picture?
the best advice i can give you is to stop enabling your employer before your life gets ruined. it's not worth it.
good luck, let us know how you make out.
Apparently I missed out some something last week since I had 30-some notifications in my e-mail...
Anyway, last week on Thursday or Friday it was nice here (about 65) so I thought I might see if I could get the forklift to run at all.
I started it up and it was chugging as usual but I was able to get it to at least rev up, so I held it at WOT for a little while (RPMs were still not that high)
It was doing its usual running bad, but after maybe a minute or two of holding it wide open, it popped a couple times and then the rpms went up and I noticed it revved up easier. I let off the throttle and it was idling normally again and revved up normally...odd.
Now it's just running really rich...any ideas there?
THe Zeinth carb was not junk back in the 70' as you say.
Matter fact it was state of the art back then. !!!!!
As well as J&S LPG!
I am thinking you are speaking from experience of the70's?
If not , check your facts!
I am !
Thread clipped by Administrator.
back in the 70s the zenith carb was junk and still is.you have a bad carb #1,Do you have a --t-- jet on the bottom of the fuel bowl? of the carb. the float should be brass, float it and see if it sinks and remember that gas is a thinner base than water.It could float in water and not gas,very decieving test with water.If the engine cranks and has a non constant crank then do the compression test and if the head gasket is blown,it wii be reght between the 2 cyls where the distributor goes in the head.Do you have water in the oil?If the compression test proves good then throw away the gas carb and look into a propane conversion.Check to see if any intake nuts are loose.the intake and exhaust are bolted on the same side and have nuts on top where you can see them and in the middle between the 2 manifolds.remember it takes three things to make an engine run,spark,fuel,compression-later
Garret
autozone (if you have 1 by you) has a tool lending program
you pay for the tool but then they refund you 100% when you return it
the tools are of eh quality
but its a good way to borrow a free tool if you have no other options
make sure your points are good and adjusted properly
good spark will be able to jump a gap of 1/2 - 1 inch with a bright blue spark
a yellow or red arc would indicate a weak spark
I swear i didn't see a drain plug when I looked before...but I will have to look again.
It seems to me, though, just judging by the fuel going through the filter, that it should be getting plenty of fuel.
Also, I tried spraying starter fluid directly into the carb while it was running to see if the engine would speed up, but it wouldn't.
I believe that the first approach would be to make sure you have an adequate fuel supply. If the tank is rusty inside it needs to be drained & flushed to clean it. The fuel tank on this model is an intergal part of the frame. Look under the frame at the tank and you should see a flush type pipe plug with either a square or hex female drive. This plug can be tough to remove, but, it will allow you to drain & flush the tank of any loose material that could be plugging the pump intake. The other suggestions are good too. However, regardless of head gasket or anything else if it's not getting enough fuel it will not run as it should.
Also, you may want to start the unit and with it running spray some type flamable fluid around the intake manifold gasket. If the gasket is bad this will cause the engine speed to increase.
Spray parts cleaner works well for this...just use adequate ventilation and do not breath the exhaust fumes when this stuff is burned.
I don't have a compression tester but I'll have to see what I can do. Maybe I can borrow one from an auto parts store.
Yes you can. Just pull the spark plug wire off the plug while the engine is running. You mentioned how the wires are new-ish so I wouldn't worry about being shocked. Even if you do get shocked it doesn't hurt, it just scares you...in a pinch I will test the spark by shocking myself.
You really should do a compression test though, this can let you in on other problems this truck may be having.
Can I do that without getting shocked?
If it's chugging and reving up slowly it's misfiring. That's exactly how those flat head Continentals react with a bad head gasket. Get it running and pull the spark plug wires off one at a time, from the cap side, and the 2 that have no effect on the way the motor runs are where the gasket blew between or do a compression test.
But, pratically overnight, would this happen??? Because that's how it occurred...it was running good one day, and then the next time I tried to use it, it didn't want to start...and if it did start, it ran very poorly, as it still is.
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