hicrop10 Posted October 5, 2020 Share Posted October 5, 2020 My 79 r model won’t start.It has been hard starting if it sit for a while,like it loses it prime.Now it won’t start at all.Checked the filter it’s fill of fuel.It will start on starting fluid but won’t run on it own.The hand priming pump,I pump it like 50 times and it doesn’t get hard.I’m thinking it may be bad,anyone know the part number for will change it out.Any help would be most helpful.Thanks.Mike Durkin. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/ Share on other sites More sharing options...
Licensed to kill Posted October 5, 2020 Share Posted October 5, 2020 Could be a leak in the fuel line on the suction side. Wont leak fuel but will suck air and prevent startup. The first thing I would do is put a fuel line from the filter housing to a jerry can of fuel and try it. If still no start then put a clear fuel line between the filter housing and injection pump and watch for air when you try to start it. Diesels are pretty simple, if it's getting fuel it's gotta go. Pooched hand pump shaped not affect it's ability to run and will only prevent you from priming the system and if the system lost it's prime, you have other issues. You could put an electric fuel pump in your temp line from the jerry can to eliminate the need for the hand pump. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-461944 Share on other sites More sharing options...
hicrop10 Posted October 5, 2020 Author Share Posted October 5, 2020 Licensed to kill,that is my plan to try and get it to start out of a jerry can.Never throught of the clear line will try that also.Thanks will let you know how I make out. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-461949 Share on other sites More sharing options...
Red Horse Posted October 6, 2020 Share Posted October 6, 2020 If pumping primer 50 times and it doesn't build pressure what does that say.? Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-461984 Share on other sites More sharing options...
Licensed to kill Posted October 6, 2020 Share Posted October 6, 2020 27 minutes ago, Red Horse said: If pumping primer 50 times and it doesn't build pressure what does that say.? It says that it isn't working properly😋. When I had a no start on my '98 WS (550 CAT) it was a check valve in the filter housing. When I had a no start on my '05 Pete (475 CAT) it was a loose fitting on a fuel line on the suction side allowing air into the system. IIRC, it both cases the hand primer would not build pressure. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-461994 Share on other sites More sharing options...
Red Horse Posted October 6, 2020 Share Posted October 6, 2020 1 hour ago, Licensed to kill said: It says that it isn't working properly😋. When I had a no start on my '98 WS (550 CAT) it was a check valve in the filter housing. When I had a no start on my '05 Pete (475 CAT) it was a loose fitting on a fuel line on the suction side allowing air into the system. IIRC, it both cases the hand primer would not build pressure. that was the point I was trying to make. My 237 has always started at touch of button. But in process of replacing steering box I took the primary off for better access. In process of pulling floor boards up, I lost a piece of throttle linkage so I made up new rod. I had all floor back in place and wanted to make sure linkage was good so I fired it up-after making sure primary was full. Ran for a few minutes then quit. Cranking and no smoke. Pulled primary and it was down well below pick up. Not being a "wrench" I filled it again with same result. And this was after I disconnected outlet at second filter just before pump. Hit the primer about 8 times got good pressure and I'm spraying fuel-again primary was full to brim t that point.. Filled it again, fired up, running well and I then shut it down and pulled primary. Sure enough it is NOT full. Called my "mentor" Danny M-Mass guys will know who I'm talking about-He quickly says I have a leak in line between tank and filter. I say.."but I checked line-no evidence"-he says "Its a suction line-its an air leak. "Check line again"..... Duh- took me 3 seconds- I 'm looking at filter housing and I see like 3 bright brass threads on hose! In process of taking filter off, I disconnected housing from firewall and in process of wrestling old box out and putting replacement in the real mechanic who was helping me and I kept moving fuel line/filter base and obviously loosened hose. Now I know what an air leak can do to a pump😎 1 Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462003 Share on other sites More sharing options...
Freightrain Posted October 6, 2020 Share Posted October 6, 2020 4 hours ago, Red Horse said: If pumping primer 50 times and it doesn't build pressure what does that say.? I had to fix the hand pump on my 237 before getting it running the first time after buying it. There is basically two ceramic discs with springs behind them that act like one way valves. Mine were dried up and stuck. Once I lubed them the hand pump works flawless. I'm not sure "IF" they have any affect on running? Never found out. Just have to unscrew the two plugs and see what you find. I wonder if the return side was stuck open, would that allow fuel to drain off after shutting it off? I know with the truck running, if you leave the hand pump loose it will pump up/down while the engine is running. I've never ran it long like that so can't say if it detrimental to fuel pressure/power? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462006 Share on other sites More sharing options...
hicrop10 Posted October 6, 2020 Author Share Posted October 6, 2020 Does anyone know the part # for the hand priming pump. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462017 Share on other sites More sharing options...
Red Horse Posted October 7, 2020 Share Posted October 7, 2020 5 hours ago, Freightrain said: I had to fix the hand pump on my 237 before getting it running the first time after buying it. There is basically two ceramic discs with springs behind them that act like one way valves. Mine were dried up and stuck. Once I lubed them the hand pump works flawless. I'm not sure "IF" they have any affect on running? Never found out. Just have to unscrew the two plugs and see what you find. I wonder if the return side was stuck open, would that allow fuel to drain off after shutting it off? I know with the truck running, if you leave the hand pump loose it will pump up/down while the engine is running. I've never ran it long like that so can't say if it detrimental to fuel pressure/power? FT-thx for prime pump lesson! Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462028 Share on other sites More sharing options...
Popular Post Freightrain Posted October 7, 2020 Popular Post Share Posted October 7, 2020 No problemo..... I had to learn it myself as I had no clue. Of course it was easy on an engine sitting on the floor in the garage. I did have to replace the transfer pump the following summer due to low pressure on a hard pull, it would run out of guts about 1/2 way up a long grade. The hand pump was fine. I put a small fuel pressure gauge strapped to the air cleaner so I could watch it on the hills. That is where I found out what was going wrong. Put a reman pump on it and she was like a new puppy again. Photo from google. Going from faded memory there is a disc on top and bottom, "inlet' and "outlet". Not really hard to figure out, but watch dropping parts if taking it apart on the truck. Though there only 2 bolts holding this onto the transfer pump, so removal would make it easier to work on a bench. 4 Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462066 Share on other sites More sharing options...
hicrop10 Posted October 7, 2020 Author Share Posted October 7, 2020 FT,that’s the pump I’m looking for.Watts don’t have one.Found one hour and a half from home,m on my way in about 10 minutes. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462070 Share on other sites More sharing options...
DavCut Posted October 12, 2020 Share Posted October 12, 2020 Evening Mike. Did the new pump do the trick? Dave Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462266 Share on other sites More sharing options...
hicrop10 Posted October 12, 2020 Author Share Posted October 12, 2020 New one had to be ordered in should be in today.If so will be in the truck today also.Will let you know. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462275 Share on other sites More sharing options...
mowerman Posted October 15, 2020 Share Posted October 15, 2020 Anxious to see the results here I also need one Milne leaks and suck air.... bob Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462453 Share on other sites More sharing options...
hicrop10 Posted October 16, 2020 Author Share Posted October 16, 2020 Got the new one in and the old dog still won’t fire,so after some choice words that we won’t mention here.I bypass the new pump and the filters and tried starting out of a can full of fuel.Runs like a Swiss watch.New pump is bad,that’s what I get for being cheap.Macks new one was $210 pai was $139,going to get a Mack one. Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462461 Share on other sites More sharing options...
DavCut Posted October 16, 2020 Share Posted October 16, 2020 On a positive note at least she ran once you bypassed the pump! Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462476 Share on other sites More sharing options...
mowerman Posted October 16, 2020 Share Posted October 16, 2020 I was wondering if maybe you didn’t give it enough time to pick up the fuel last time I had a prime issue blew air into the fuel tank .... bob Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462492 Share on other sites More sharing options...
Freightrain Posted October 16, 2020 Share Posted October 16, 2020 Like I said, there isn't much to them. Tear it apart and see how the sealing surfaces are. Might have a piece of gunk in it from the get go? Poor machining? Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462494 Share on other sites More sharing options...
mowerman Posted October 16, 2020 Share Posted October 16, 2020 I thought about just by passing the damn thing I really don’t need it anyway but it is handy to have .... all my lines need to be changed But I will certainly try that before..... but mine is a lot easier to get to .. bob Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462496 Share on other sites More sharing options...
hicrop10 Posted October 23, 2020 Author Share Posted October 23, 2020 The truck still didn’t run with the new pump from Mack on it.After thinking about it I changed the lines on the pump around,sure as shit when they rebuilt it they changed the suction side to the push side.Truck runs great now,will take it out on Saturday for a spin. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462897 Share on other sites More sharing options...
mowerman Posted October 23, 2020 Share Posted October 23, 2020 Aaaaaaaaaaaaaarite thanks for keeping us posted..... glad you figured it... bob Quote Link to comment https://www.bigmacktrucks.com/topic/64470-won%E2%80%99t-start/#findComment-462898 Share on other sites More sharing options...
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