Official Cummins QSC-500 Thread

I follow Frank's shock protocol to the letter every spring, change my racor 30M filters at least twice every season even though they still appear clean (certainly not black like they were when I first got at it after driving it up 40 hours from VA), change my secondaries every spring, and run Bioguard and Diesel Kleen with every tank. I still get the black specks in the racors.
 
Changed the racor filters and went for a test ride to make sure there were no leaks, to my surprise the boat ran so much better. I didn't realize they made that kind of difference. Changing the fuel pumps later this week. I read and printed Franks post about Diesel fuel management last year, and then did nothing about it. Not making that mistake again.
 
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Fixin' to have the valves adjusted and the heat exchangers cleaned. Words of advice?
 
John,

Talk to the guys at TIM if you haven't already. They bought a recirculating cleaning system several months ago that saves having to disassemble any of the cooling system to clean it, plus it also cleans everything seawater runs thru at the same time. Perhaps some other folks in town have the same system, but it sure does a good job for a lot less labor than taking everything apart.
 
Hampton said:
Fixin' to have the valves adjusted and the heat exchangers cleaned. Words of advice?
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Just had my QSB's cooling system done. Because of vulnerability of recent Cummins aftercoolers (which I think may apply to the QSC), Prince William Marine (which I think is very good) did disassemble those. They told me it was done just in time as a gasket was about to go. Core was OK so it didn't need a bath, just an acid clean at the intake side. Once the put the aftercoolers back on they did a recirc cleaning on the entire system.
 
Frank, I'm glad to get your nod of approval on the process. They will be doing the work. I'll talk to Roland about the aftercoolers and see what he recommends.

Thank you guys.
 
Couple of things:

1. Thanks Frank and Alex for the advice on changing the belts. One of the belts was beginning to break down, and had some chunks of rubber missing. Avoided having a very bad day coming. Changed them in 15 mins with Alex's instructions. I'll do each year.

2. Question: when I change the spin on fuel filters, do I need to fill them with fuel?

3. Question: see attached picture. Both engines have a small leak on the top of the head cover coming from a small rubber fitting (circled in red) that attaches to a filter cover. The rubber fitting appears to be cracked. Do I replace just the rubber fitting or does the filter cover need to also be replaced?

Oil leak pic.jpg

Thank you,

Scott
 
sb in gp said:
Question: when I change the spin on fuel filters, do I need to fill them with fuel?
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They do need to be full of fuel and purged of all air or you will air lock your engine. If you fill them with a fuel can, you risk introducing particles that can be damaging to the fuel system. What you need to do is spin on the empty filter and cycle the ignition switch from off to the accessory position until you hear the pump stop spinning. Be careful not to crank the starter. Repeat the off/accessory cycling 10 times and spin off the filter enough to see if the fuel has reached the top. If not, repeat the off/accessory cycling 5 more times and check again. If the fuel is at the top, it will spill out a bit as soon as you spin off the filter enough to create a gap between the gasket and housing. When it appears to be full, cycle off/accessory 3 more times and start it up.
 
I don't know about QCS500s but 450Cs have manual pump. I prefill my filters and then use the manual pump to bleed the air out of the system. When I know that I'm done with bleeding air I advance the throttle a bit and engage the starter. Usually, it takes only single attempt and the engines are fired up and running. Advancing throttle helps to purge minor air pockets allowing the engine to remain in running state. It only takes few seconds to feel that I can bring the throttles gradually back down.

If I understand correctly, Mike described the procedure with electrical fuel pumps (I guess this is what QCS has). This is similar to what I do for my Onan genny with electrical pump. I press start button and listen for the pump to cycle. I know that usually it cycles for 15-20 seconds before the started is engaged, so I depress the button preventing to trigger the starter. After cycling the pump 6-8 times I allow the starter to kick off. Unlike with manual pump on the mains, I can't tell when the air pockets are gone. So, genny usually stoles few times before it gets back to normal running state.
 
sb in gp said:
3. Question: see attached picture. Both engines have a small leak on the top of the head cover coming from a small rubber fitting (circled in red) that attaches to a filter cover. The rubber fitting appears to be cracked. Do I replace just the rubber fitting or does the filter cover need to also be replaced?

View attachment 37693
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Got 1 question answered. Anyone have an idea on the little oil leak?

Thanks,

Scott
 
I had the valves checked on my 2008, 630 hour QSC's. Still within .002 inches tolerance. They need to be checked every 5000 hours or 4 years - CYA. The genny was adjusted for the 3rd time - 2000 hours. They DO need it.

I had the heat exchangers all flushed. The main engine temps dropped from as much as 179 (normally 177) to a solid 174, but there was definitely a lot of calcification in there. Heat distribution should be more consistent as well.

I had the props tuned. I thought I had done this before, but I can't find the paperwork. The stbd has always had higher fuel flow (.3 gallons or so), higher load (2%), the rudder sat at 2* stbd on auto in a straight line....... They found one blade on the stbd side with too much pitch. Now, the port has 1% more than the stbd - time to earn its keep. I was amazed to see the rudder run at 0*.

I had the coolant flushed and replaced on all three engines. Ready to cruise!

New bottom paint - 3 1/2 years. I buffed/waxed the sides and back end - 100% - 3 full days.
 
Has anyone found a suitable replacement belt for the Onan MDKBL generator? I can find only 1 source online and they are $40 plus shipping. Wondering if anyone found an equivalent part that can be sourced less expensively.

Scott
 
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The generator's engine is a Kubota D1105; that's helped me find some filters and such but I have never changed the belt. Using the engine model and looking on line, I think the part number for the belt is V-16282-97010. Looks like it's available for $15-$20 at several places. You may be able to find the belt at a local source; RV dealers are usually good sources.[h=2][/h]
 
alnav said:
The generator's engine is a Kubota D1105; that's helped me find some filters and such but I have never changed the belt. Using the engine model and looking on line, I think the part number for the belt is V-16282-97010. Looks like it's available for $15-$20 at several places. You may be able to find the belt at a local source; RV dealers are usually good sources.[h=2][/h]
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Thanks Al. Exactly what I was looking for. Found filters and belts for about half the price of the Onan distributors.
 
sb in gp said:
Thanks Al. Exactly what I was looking for. Found filters and belts for about half the price of the Onan distributors.
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So I just saw a criticism on another thread about those that buy non-OEM part to save a few bucks. Don't want to be penny-wise and risk damaging my expensive toy. Does anyone see a problem with using Kubota parts in an Onan gennie, since Kubota is the true OEM of the motors? I suppose the only issue could be if the belts and filters are made different for the marine environment, which seems unlikely.

Scott
 
I use after market parts quite often, depends on what it is. No problem with belts. But sometimes the "good stuff" isn't a lot more money. When my NAPA dealer couldn't cross the Onan number for the belt, I went online to see prices between 30 and 50 bucks. I then tried my local Cummins parts department, $25 in stock. Pleasantly surprised.
 
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sb in gp said:
So I just saw a criticism on another thread about those that buy non-OEM part to save a few bucks. Don't want to be penny-wise and risk damaging my expensive toy. Does anyone see a problem with using Kubota parts in an Onan gennie, since Kubota is the true OEM of the motors? I suppose the only issue could be if the belts and filters are made different for the marine environment, which seems unlikely.

Scott
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I buy filters for my Cummins/Onan genset at the local Cummins dealer. They say Kubota on the box.
 
sb in gp said:
So I just saw a criticism on another thread about those that buy non-OEM part to save a few bucks. Don't want to be penny-wise and risk damaging my expensive toy. Does anyone see a problem with using Kubota parts in an Onan gennie, since Kubota is the true OEM of the motors? I suppose the only issue could be if the belts and filters are made different for the marine environment, which seems unlikely.

Scott
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Scott,

I was under the impression that Kubota was the actual OEM (Japan) engine maker for Onan. This is why we see some parts coming from Cummins say Kubota on them. I don't have it in front of me, but if I recall, the fuel filter is a good example. For oil filter I'm using Fleetguard LF3536.
 
Kubota filters should work, however, I use several pieces of off-road Kubota diesel equipment and have found that tractor dealers have gone nutty on pricing for Kubota brand parts. You will probably save money buying Cummins/Onan parts online and staying one filter change ahead of your current need so it isn't an emergency the next time you need a filter.
 
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