Scott W
Hey guys, new to the forum and looking for a little advice/assistance. I have a Propane Generac 45KW stand-by generator (Model 005262-0) that won't start. The unit was running well and started fine every Friday for it's weekly exercise period until a few weeks ago. Now it cranks but will not fire. I had a chance to tinker with it last night and I got it to run but only after removing the air filter assembly and cupping my hand over the venturi/actuator assembly. Once it fires, it takes off and runs fine but when I shut it down it won't start on its own. I'm thinking a fuel regulator or solenoid may be bad but I've not worked around these units much so I'm reaching out to folks who are much smarter than I for guidance :)

Thanks in advance, Scott
Quote
78buckshot
Hey Scott, welcome to the forum. You should find a "cold start solenoid" attached to the demand regulator. It will have two small black wires, these have a history of poor connections and not letting the solenoid open for fuel enrichment on start-up. No rocket science, just take it apart and tighten the terminals. The cold start solenoid is the one with the smaller rubber hose off the tee.
Quote
Scott W
78buckshot;53005 wrote:
Hey Scott, welcome to the forum. You should find a "cold start solenoid" attached to the demand regulator. It will have two small black wires, these have a history of poor connections and not letting the solenoid open for fuel enrichment on start-up. No rocket science, just take it apart and tighten the terminals. The cold start solenoid is the one with the smaller rubber hose off the tee.


Thanks for the welcome, and speedy reply! I checked both the coil solenoid (larger rubber hose that terminates at the air filter assembly) and the "cold start" solenoid (smaller rubber hose that terminates at the intake manifold) and both solenoids energize when the manual start button is pressed. I even removed both and placed a screw driver in the solenoid shaft and the magnet is definitely working when the start button is pressed. I also disassembled the cold start solenoid to ensure the plunger was moving freely (and it is). Am I missing anything else?
Quote
Peddler
You need to check fuel pressure coming to the unit to make sure it isn't over about 12" water column or the fuel valve won't open.
Quote
Scott W
Peddler;53013 wrote:
You need to check fuel pressure coming to the unit to make sure it isn't over about 12" water column or the fuel valve won't open.

I disassembled the regulators and cleaned everything up. The generator will start now but it cranks for a few seconds before it catches. I disconnected power to see if it would crank and load and it did. Ran it loaded for about 30 minutes and everything went well. I guess it just needed to be run a little longer than the weekly exercise period. Thanks to all for the advice and troubleshooting tips. I know much more about my machine now thanks to you guys! Cheers, scott
Quote
murphy
There will always be a starting delay if the engine has not run for several hours. The engine has to produce a vacuum at the demand regulator before the regulator will open. Gas then has to flow to the engine before it can start running.
Quote
Scott W
murphy;53016 wrote:
There will always be a starting delay if the engine has not run for several hours. The engine has to produce a vacuum at the demand regulator before the regulator will open. Gas then has to flow to the engine before it can start running.


That makes sense! I guess I never really paid attention to how long the engine cranked before firing. After taking apart the regulators, I noticed the baffles on both sides need to collapse and not expand to allow LP into the manifold. I assume that is why higher inlet fuel pressure is NOT a good thing (i.e. more vacuum req to overcome the higher pressure). Is this a correct assessment? If not, I welcome the opportunity to be enlightened... :)
Quote
murphy
High fuel pressure is not a good thing. The fuel pressure specified for the unit is where it needs to be.
Quote
Cobranut
Fuel pressure on gaseous fueled engines can also affect the mixture.
Too high a pressure can make the mixture too rich, wasting fuel and causing poor performance.
Quote
Scott W
Thanks for all the info guys! I hope to contribute to the forum in the future and help someone out as much as ya'll helped me! Cheers!👍
Quote