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Topic: Onan 4000 Generator cranks, but won't start.

Posted By: Attila on 05/02/10 10:04pm

I just got a brand new 5th wheel and followed the break-in procedure on my Onan RV-QG 4000 EVAP Gen set. I hadn't ran the generator for anout 5 weeks and it wouldn't start today. I noticed the fuel was low so I put 10 gallons of gas in the trailer.

The unit cranks, but won't kick over. Oil looks fine and the level is good. I primed the fuel system, but is it possible to flood the gen set ? I haven't looked at the spark plug yet, but with a new gen set that was running fine 5 weeks ago I'm kind of at a loss. It's too soon for a service call and I'm not getting any codes.


Posted By: Golden_HVAC on 05/02/10 10:59pm

If it is flooded, you can usually smell the un=burned gas in the exhaust. Try it in the morning, and if it fires up, then it might have been flooded, and fixed itself overnight.

Is there a setting for altitude? A small black dial on the carburator? Set that for about 1,000 feet, and it seems to work best for me.

It might also be possible that the battery is run down enough that it is cranking slowly, can you charge the battery? If it was plugged in, then the battery should be full, but check the meter anyway. If below 1/3 or 1/4, then the battery might need recharging.

Good Luck,

Fred.


Posted By: M GO BLUE on 05/03/10 07:48am

dhallenbeck wrote:

Same problem, how do you prime it?


On my Onan 5500 gas generator I can hold the stop button down (located on the front of the generator) and that primes it...




2005 Chevy Silverado 3500 dually CC/LB Duramax/Allison
2008 Jayco Designer 35RLTS fifth wheel
Onan 5500W Marquis Gold gas generator (HGJAB - 1038D)


Posted By: Handbasket on 05/03/10 04:23am

If you can plug it in for recharging, try that. In my B's and C, I've found that my small Onans will sometimes sound like they're cranking fine on just the battery, but will need the extra voltage from the running engine's charging system to actually start.

Jim, "Mo' coffee!"


'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')


Posted By: Attila on 05/02/10 11:24pm

Thanks Fred,

I'll try again tomorrow. It does have an altitude dial which I has set at sea level. I'll set it to 1,000 feet and try again later.


Posted By: dhallenbeck on 05/03/10 07:44am

Same problem, how do you prime it?


Posted By: kg5388 on 05/03/10 04:29pm

my Onan RV-QG 4000 EVAP Gen set


this was a better try of letting us figure out which model you have but the model number is better as it tells us more in detail of what you have and the last letter of the model is the spec letter

they started at A for the spec letter and every time they make a change they change the spec letter

if they take a spec A and change the carb or ignition parts or any part of the genset they change the letter to B and so on for every change

it helps to check for product service bulletins and trouble shooting steps to parts for that genset


Posted By: kg5388 on 05/03/10 04:24pm

dhallenbeck wrote:

Same problem, how do you prime it?


if the genset is gasoline or diesel and has a red light in the start/stop switch on the genset you can push and HOLD stop and after a second the red light will come on and stay on

when the light comes on the fuel pump will run until you release the switch or 3 min are up


Posted By: kg5388 on 05/03/10 09:02pm

Title: Genset Cranks But Does Not Start-Fault Code 36 and Related Fuel Pump Faults
Model(s) HGJAB, HGJAE, KY, KYD, KV and KVD
Background/Description:
It has come to our attention that the generators mentioned in this document were manufactured
with a fuel pump that did not meet Cummins Onan standards of quality and reliability.
To reduce the cost of diagnosing a common failure mode, this notice details the Temporary
Repair Practice (TRP) implemented for the afore mentioned models with the following fault
conditions.
?? Genset Cranks but does not Start – No Fault Code
?? Overcrank – Fault Code 4
?? Overfrequency – Fault Code 14
?? Underfrequency – Fault Code 15
?? Overspeed Fault – Fault Code 31
?? Genset Stopped without Fault Condition - Fault Code 36

KY and KYD
?? Applicable for sets built after April 2008 and before serial number
F090004481 with less than 50 hours runtime.


Posted By: kg5388 on 05/04/10 09:22am

there are a few of us that used to be in the RV genset repair busness and some that still are in the business.


there were more members that were/are in the business and helped but they got tired of playing the guess which generator I have game and quit helping.


Posted By: kg5388 on 05/03/10 08:58pm

Title: Crank but not starting and/or low compression in KY models
Model(s) KY, KYD, and MKY
Background/Description:
Cranking but not starting due to low compression caused by broken valve springs on a KY
generator set.
Generator sets may crank but not start. This may be caused by a premature failure of one or
more valve springs. This would cause the valve not to seal resulting in low compression.
Gensets built between February 2008 and April 2008 have the highest rate of failure. A solution


this is why the first letter of the serial and 2 numbers after it is so IMPORTANT

take the air filter out put your hand in the air filter housing and try to start the genset do you feel suction if not you may have a bad spring.

feel suction then put a spark plug in the boot and hold against the engine with insulated pliers do you have spark?

pull the fuel hose off the carb and put in a container push and hold stop so fuel pump will run does fuel come out?


Posted By: Attila on 05/03/10 09:55pm

kg5388 wrote:

Title: Genset Cranks But Does Not Start-Fault Code 36 and Related Fuel Pump Faults
Model(s) HGJAB, HGJAE, KY, KYD, KV and KVD
Background/Description:
It has come to our attention that the generators mentioned in this document were manufactured
with a fuel pump that did not meet Cummins Onan standards of quality and reliability.
To reduce the cost of diagnosing a common failure mode, this notice details the Temporary
Repair Practice (TRP) implemented for the afore mentioned models with the following fault
conditions.
?? Genset Cranks but does not Start – No Fault Code
?? Overcrank – Fault Code 4
?? Overfrequency – Fault Code 14
?? Underfrequency – Fault Code 15
?? Overspeed Fault – Fault Code 31
?? Genset Stopped without Fault Condition - Fault Code 36

KY and KYD
?? Applicable for sets built after April 2008 and before serial number
F090004481 with less than 50 hours runtime.


Where are you guys getting this information ? I'm looking on the Onan website, but not seeing these bulletins ?

By the way:

Model No: 4KYFA-6747K Spec: K
S/N: E090243098

* This post was edited 05/03/10 10:27pm by Attila *


Posted By: Attila on 05/03/10 08:36pm

Onan RV-QG 4000 EVAP. Model KY Spec K. The trailer is in storage and there's no electrical. Before I take the battery out or haul it to the house can I plug the trailer into the truck (with it running)to see if I can get enough spark to kick the gen set over that way ?

I'm having a hard time believing that a solenoid and any other component is the problem since the unit is brand new with less than 15 hours. Just taking a simple process of elimination before I take anything apart. There are no codes present and I've tried to prime and start from the remote panel and from the genset directly.


Posted By: cptdondo on 05/03/10 09:26pm

One more random thought: The way my Onan is plumbed for gas, the fuel pump doesn't have enough oomph to prime itself as it takes its supply from the fuel return line. Start the engine, let it run for 30 seconds, leave it running, and then try to crank the Onan.


2001 Roadtrek 200 Versatile
1989 Isuzu Trooper toad


Posted By: kg5388 on 05/04/10 11:03pm

your genset was made in may 09 and has a 2 year warranty with 3rd year major parts to a limit of 2000hours.

Maintenance items oil/filters and not following owners manual rules for exercising or service intervals of the genset are not covered by warranty

take the fuel line off the carb point it in a can and hit prime** be careful with gas and sparks** if fuel comes out you got a carb problem

no fuel then if you look on the front of the genset there are 2 silver torx screws that hold the control/metal plate the starter solinoid is on

remove the 2 screws and lift up on the plate

the fuel pump is under the control it's round brass cylinder

make sure the black wire from the pump is secured to the ground bolt

the brown wire is the positive wire to the pump pull it loose and connect a meter to it and ground/unpainted metal and try to prime the genset

if you get 12 volts during prime then it maybe the pump

if you get 12volts to the pump you should remove the fuel line to the fuel filter under the genset remove filter and make sure it is clear if it is stopped up with trash from fuel lines being made/installed in rv it will not be covered by genset warranty

if the filter is clear then reinstall and hook a fuel hose to the filter and drop into a can of gas *be careful of gas and sparks*

try to prime the genset as a loose clamp where the fuel line ties into the fuel tank or a rubbed hole in the line will allow the pump to suck air and not fuel-think drinking straw crinked

a hole or loose clamp kinked hose is not covered by genset warranty

if you don't get 12 volts it's the controller


that was a service bulletin that allows the techs to know there was a problem with some pumps to help fix problems quicker

if it is a bad pump yes it will be fixed under warranty

* This post was edited 05/04/10 11:14pm by kg5388 *


Posted By: ranchmkt on 08/22/10 05:54pm

Can this be heat related? mine only acts up when outside air temp is in the 90s. Can the fuel pump get too hot and vapor lock? This is driving me nuts always quits at the worst time and not at the dealer.

And it is a code 36 checked as per last thread. checked out.


Posted By: Attila on 08/22/10 08:51pm

I just wanted to get back to everyone. I took it to the dealer and it ended up to be the fuel pump. They fixed it for free which was great, but they just put the same type in again.


Posted By: Attila on 05/04/10 09:34am

Thanks for the advice everyone. I'll follow the steps and then get back on the forum if I get stuck.


Posted By: Attila on 05/04/10 10:44pm

Worked on this problem some more today. I originally thought I flooded the unit, but I came back two days later and it still wouldn't start. I noticed that when I primed the genset using the Prime/Stop switch the fuel pump was dead silent. No activity whatsoever. I also primed it for 30 seconds like the manual said in case the lines were empty. I removed the air filter, opened the choke, and could not smell any fresh gas.

kg5388s post makes me think it's the fuel pump. Either it's bad or I'm not getting power to it. I can try to power the pump up directly to see if it'll run, but if the genset isn't getting any fuel that should explain why it's cranking and not starting. Any other thoughts ? It's a brand new genset so was this a recall item and can I at least cover this under warranty ?


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