dickandlois Report post Posted March 19, 2020 The information you offered clears up how you genset is installed. Yes from your info. the generator removal requires a fork lift or a pallet jack . in that case there is a section of the front cowl that needs to be removed so the unit will clear, plus a few other items. I do feel for you working under the coach is a very tight space. Glad you are home. Offers more options. I might be able to find a part number for the starter solenoid , but if it does not work properly on the bench and you are planing on replacing the starter. Open the new one and run the same test you ran on the OEM unit. Should they both react the same, then you need to run the jump test used on the bench when the new starter is installed, to see if the new one engages. Should the starter not in gauge, Then the group need to think of other options. If it does spin the engine. Reconnect the OEM power wire to the solenoid. Plug the supply side fuel line and see if the starter spins up. It should, but if not then one needs to consider a wiring issue between the control board and the starter or the control board comes into play ! I would strongly suggest placing 12,000 pound jack stands under each frame rail while working under the coach !!! Air bags with no air in them. Any damage to the air supply lines or bags can cause a quick loose of air. Should one decide to remove the generator, you might need to move them to under the axle, so the forklift or pallet jack has some extra room, Width wise, the trade off is height. The QD 7500 series generators weigh in at close to 750 lbs. The jack stands need to be on wood blocks or concrete to keep them from sinking into the ground. As you may have found out, you need to remove the fuel filter to get access to the starter and you will get fuel from the pump running out of the fuel system. Can get messy ! While on the fuel filter issue, how long has it been sense it was replaced? Good Luck at your appointment. Seeing them more often these day also ! Rich. STARTER SOLENOID REPLACEMENT WARNING This test involves high electrical currents, strong arcing and moving parts that can cause severe personal injury. Do not conduct this test near fuel tanks or when flammable vapors are present. Wear safety glasses. Keep fingers away from the pinion gear. The starter solenoid is separately replaceable. To determine whether the problem is in the solenoid or in the motor: 1. Secure the motor assembly in a vice after it has been removed from the genset. 2. Using a heavy jumper cable, because of the large currents involved, connect the motor terminal on the solenoid (the one closest to the motor) to the positive (+) terminal on a 12 volt battery. 3. Using a heavy cable from the negative (–) terminal on the battery, briefly touch the mounting flange on the motor. • If the motor does not spin up quickly and smoothly, replace the motor/solenoid assembly. • If the motor does spin up quickly and smoothly, the motor is probably okay: replace the solenoid. The solenoid is removable by disconnecting the motor lead from the solenoid terminal and removing the two solenoid mounting nuts. When installing a new solenoid, make sure the solenoid plunger engages the shift fork. Share this post Link to post Share on other sites
f375818 Report post Posted March 22, 2020 Finally received new starter motor. Pulled the old motor (again) and bench tested both motors side by side using the same power supply (12v btry). Both motors reacted the same. Good spin up with the pinion gear slung forward. The only difference was the new motor slung the pinion gear forward with at least 10 times the force as compared to the old motor. Installed new motor in the genset and after priming the new fuel filter it cranked right up with very little effort. Going back to my original post, "Is it possible that the start motor reacts as indicated during bench test (no load) but does not have enough torque to turn the genset (max load)?", it appears that is exactly what was happening. Now, why did that happen? Apparently a solenoid that was working but certainly not very efficiently. As some have posted, it may simply be that the contacts need to be cleaned up. I'll take it apart next week and see what i can do. More info...Found a sticker near top on onan case that said engine type is in fact a Kubota model D722ES with output 14.9KW. Not sure why they would include that output on a 7.5KW genset. Who cares, it works for me. Starter motor has no multiplier or other gearing. Pinion gear engages directly with the flywheel to turn the engine. Thanks to all who replied to this topic without judgement and yes, thanks to Herman also even if he is a little quick to judge others. Share this post Link to post Share on other sites
dickandlois Report post Posted March 23, 2020 Glad to hear the Generator started. Also, Thanks for the information about the Kubota engine. Now there is something this old guy can dig into to see where it goes. The math works out to just a little over 10,000 KW of electrical power, but the generator connected to it might be for the standard 7.5 system. Maybe Onan just ran short of engines and substituted a Kubota . A number of the Kubota powered generators are wired for 220 volts. You might have noticed some differences regarding the oil fill, dipstick and filter location? Could you post the Serial number of your unit? Why it works so well question. Sure sounds like the solenoid on the new starter works much better, through in force is much higher and there is much more current passing through the solenoid contacts, increasing the starter torque. You did find a loose ground connection and that could have degraded the winding in the solenoid. Found the engine specs. Plenty of HP, but it 's specification sheet mentions Power output at 3600 RPM. That means Onan set it up to run at 1800 RPM. To match the wiring commingle found in most coaches with a standard wiring setup for a single phase split winding. This lowers the HP, but gains fuel economy and would have an output of 7500 KW. If the original poster supplies the serial number information, there might be more information to post. Rich. Share this post Link to post Share on other sites
manholt Report post Posted March 23, 2020 Rich. He certainly has enough power in that Generator to run anything he wants! 😂 F375818, glad this came to a good ending for you! Stay safe and please come back to forum. Share this post Link to post Share on other sites
f433921 Report post Posted March 23, 2020 I have pulled apart several solenoids that look similar and was able to repair them by just removing studs and rotating them 180 degrees and removing the disk from the shaft and turning it over. Not as good as new contacts but got may more years of service out of it. Jim Share this post Link to post Share on other sites
f375818 Report post Posted March 24, 2020 Rich, Serial # of unit: A0608781125 Jim: take a look at the lower picture posted by DickandLois on 17 Mar on page 2. I removed the solenoid from the starter. It doesn't look like the guts will come out of it because of the moulded metal cylinder that extends to about 3/4 of the way to the back. Looks like the porcelain (back) part was inserted into the cylinder and then the cylinder was crimped down with some sort of special tool. I'm sure that i could get it apart by prying on the crimps but would probably bust the porcelain housing in the process. No big deal as it don't work like it is. Still have not found a replacement part #. Yoke on the pinion gear is good as is the plunger in the solenoid so the problem has to be with the innards. Share this post Link to post Share on other sites
dickandlois Report post Posted March 24, 2020 Thanks for the information. The original part number for the starter solenoid 191- 2216, but it looks like that has been superseded by 226-4257. You might be able to take the OEM unit to NAPA and see if they could match it up Kubota Starter number is 191-2229, but they do not brake down the solenoid number. The 2 look to be interchangeable. Your genset is a Onan, but built with a Kubota engine. Looking into what and how the 2 got related could prove interesting. They want one to replace the starter not rebuild them. Rich. Share this post Link to post Share on other sites
manholt Report post Posted March 24, 2020 Rich, in 1990 Cummins sold 27% of it's Stock to Kubota & in 2010 stopped making Onan engines! Interesting to note: Dodge Ram trucks, first ran Kubota engines and then changed over to Cummins...another note: Kubota is a revers injection engine and LOVES to eat glow plugs! Share this post Link to post Share on other sites
dickandlois Report post Posted March 24, 2020 25 minutes ago, manholt said: Rich, in 1990 Cummins sold 27% of it's Stock to Kubota & in 2010 stopped making Onan engines! Interesting to note: Dodge Ram trucks, first ran Kubota engines and then changed over to Cummins...another note: Kubota is a revers injection engine and LOVES to eat glow plugs! Kind of stuck with the Kubota engines for now. The change appears to have been made to meat the EPA requirements. Kubota is a revers injection engine and LOVES to eat glow plugs! Where did that little tid- bit come from? Rich. Share this post Link to post Share on other sites
jleamont Report post Posted March 24, 2020 Kubota is big in construction equipment, mini loaders, skid steers, mini excavators, mulch blowers, straw blowers and Hydro seeders. I cannot say I have ever had a bad experience with one of their products. Share this post Link to post Share on other sites
f433921 Report post Posted March 24, 2020 I has the same 3 cylinder Kubota in my tractor ran for 20 years never had a glow plug failure or starter failure. Jim Share this post Link to post Share on other sites
