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Grove MZ46c manlift engine trouble

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
I hope someone might have an idea on the problem I have with my old MZ46c manlift. It has started to run a little rough and only runs for about 15 to 20 minutes then it revs up to above the high speed range then dies. After a while or over night it will start again. In hot weather it doesnt want to run for more than a few minutes. I am wondering if it is one of the electronic governors or speed controllers heating up and failing then recovering once cold.?? It has the ford LRG423 engine, barber colman f4jl governor and a syncro start over speed contoller.
Any advice would be most appreciated. Also any knowledge of where I could get replacement parts? It hard to find manlift wreckers
 

03hdrk

Well-Known Member
Joined
Aug 28, 2015
Messages
127
Location
N TX
Please don't hide all your conversation. I am curious to hear was the issue(s) are. Kind of defeats the purpose of this site to talk in private.
 

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
Hey Just an update. i still have the issue but it runs ok on Propane. Im wondering if one of the brain boxes heats up and disrupts the fuel supply circuit as it seems like the shut off solenoid and the fuel pump quit. Looks like they are on the same circuit. Also think the carburetor is a bit messed up maybe. We have taken it apart and cleaned it and fixed the choke but maybe to much messing with it.
now the thing wont move forward or back, everything else works. Checking relays at this time.
 

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
I hope someone might have an idea on the problem I have with my old MZ46c manlift. It has started to run a little rough and only runs for about 15 to 20 minutes then it revs up to above the high speed range then dies. After a while or over night it will start again. In hot weather it doesnt want to run for more than a few minutes. I am wondering if it is one of the electronic governors or speed controllers heating up and failing then recovering once cold.?? It has the ford LRG423 engine, barber colman f4jl governor and a syncro start over speed contoller.
Any advice would be most appreciated. Also any knowledge of where I could get replacement parts? It hard to find manlift wreckers
Update, still having the same trouble, at the end of the summer it wouldnt run at all on propane or gas. Fuel starving??. I tried starting today as its cold and in ran great on propane. Its been 2 months since I messed with it with a mechanic friend trying to get it running. SO…. Could it be heat affecting one of the controllers?? Or even a relay?? Any thoughts would be a help please!!
also is there a anywhere that would have spare parts for this grove mz46c?? Thanks
 

03hdrk

Well-Known Member
Joined
Aug 28, 2015
Messages
127
Location
N TX
Minnpar is the grove experts, I think. I know that they quoted me work on my controller if I sent it to them. Mine is a AMZ66 so I don't know about the design on yours. I would focus on gas or propane, but not both. If yours has modules or computers then I think your in for a hard problem to find. Start with the device that is used to kill it. Is it being starved of fuel to kill it, like a solenoid on the propane line, if so, figure out what it takes to pull in that solenoid - say 12v and see if that is at the solenoid. Then go from there. A multimeter would work if you are familar with one.
Sounds temp related and any coil can act that way, whether in a relay or on a fuel shutoff. But any computer type device can also act up when hot.

I would imagine, that if your machine does not have an ecm, but just has some throttle devices related to starting and running, then you could probably replace the devices with a "off the shelf governer" I have done this on generators and even had them where a input 12 volts can make the governer go to a a set rpm. Governers of America is who I talked to. Of coarse an actuator and a speed sensor will have to match the governer. Your machine will have to be worth a lot to you to go through the trouble though.
 

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
Minnpar is the grove experts, I think. I know that they quoted me work on my controller if I sent it to them. Mine is a AMZ66 so I don't know about the design on yours. I would focus on gas or propane, but not both. If yours has modules or computers then I think your in for a hard problem to find. Start with the device that is used to kill it. Is it being starved of fuel to kill it, like a solenoid on the propane line, if so, figure out what it takes to pull in that solenoid - say 12v and see if that is at the solenoid. Then go from there. A multimeter would work if you are familar with one.
Sounds temp related and any coil can act that way, whether in a relay or on a fuel shutoff. But any computer type device can also act up when hot.

I would imagine, that if your machine does not have an ecm, but just has some throttle devices related to starting and running, then you could probably replace the devices with a "off the shelf governer" I have done this on generators and even had them where a input 12 volts can make the governer go to a a set rpm. Governers of America is who I talked to. Of coarse an actuator and a speed sensor will have to match the governer. Your machine will have to be worth a lot to you to go through the trouble though.
Thank you so much for that advice. I will be doing as suggested. I didnt know minnpar worked on controllers.
Yes it has a ECM. I have also changed out the relays on the engine side and replaced the fuel shut off on the gas side.
 

Zewnten

Senior Member
Joined
Apr 2, 2018
Messages
569
Location
Earth
Is it getting gasoline to the engine, fuel pump working fuel filter clean. Is it getting spark? Is it timed right? Had a genie with the same engine and multiple issues caused a similar scenario. Fuel pump and filter were bad finally taking out the gasoline side. The propane side had a regulator and mixer issue. On top of that it had a wiring issue from DIY harness repairs that prevented the ECM from knowing which fuel it was supposed to be advancing or retarding the engine on.
 

Vetech63

Senior Member
Joined
Aug 10, 2016
Messages
6,543
Location
Oklahoma
Sounds like fuel starvation to me. A controller issue would have affected the operation on both gas and propane from the beginning. Propane systems have a filter inside the regulator that can get plugged also.
 

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
Is it getting gasoline to the engine, fuel pump working fuel filter clean. Is it getting spark? Is it timed right? Had a genie with the same engine and multiple issues caused a similar scenario. Fuel pump and filter were bad finally taking out the gasoline side. The propane side had a regulator and mixer issue. On top of that it had a wiring issue from DIY harness repairs that prevented the ECM from knowing which fuel it was supposed to be advancing or retarding the engine on.
Yip spark is good and timing is good. It ran well on both fuels for a couple of years, then the problem started. Thanks for the reply though and will double check. Those again!
 

Phil Price

Member
Joined
Nov 20, 2019
Messages
7
Location
sequim, Wa
Sounds like fuel starvation to me. A controller issue would have affected the operation on both gas and propane from the beginning. Propane systems have a filter inside the regulator that can get plugged also.
The plugs are wet on gas. But I havent really checked filters on the propane side so Thanks for that suggestion, will check that out!
 

T&M Painting

New Member
Joined
Oct 5, 2022
Messages
2
Location
Murrieta Ca
Hey Phil, I still have this same issue. I have tried to connect Woodward Part# DPG-2345-002. This is supposedly the replacement part number for our DYN1 controllers. I am assuming that your machine still has the original blue controller from barber coleman. I have tried to no avail to get this new controller to work. I got stuck with the signal wires from the distributorless ignition. I feel as though I am so close to getting it working with the new controller but I am losing hope.

On a side note I do have 2 identical MZ46c's sitting right next to each other. I ave swapped the blue barber coleman controllers over and the issue followed. 10 mins of running then just dies after the machine heats up.

Lets see if we can put our heads together to get our machines working! I have attached the manual for the "new replacement controller".
 

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