CH613 E7 350 fuel delivery problem

[Noland]

I've got a 95' CH613 with the E7 350 engine. Recently it has been hard to crank meaning it turns over fine but it seems like it's not getting fuel. For awhile it would start with ether so I figured maybe it was loosing prime overnight. Then I started priming before trying to crank it and that working a few weeks. Now it won't crank at all. It runs until the ether is gone and it won't crank using the primer. Does anybody out there have any suggestions? 

[mrgumby]

Did you check the lift pump are your filters full

[Noland]

No sir I havent checked that yet but I will tomorrow. So if they are not full whats the next thing to check? I just read on another forum that a guy had a similar problem and it turned out to be a fitting on a fuel line worn out causing the problem. 

[fjh]

Check plastic line from the fuel pump to the head for wear and tightness check  the jumperline betwwen the heads for leaks and tightness!

[Noland]

I checked the filter and it was half full. All the braided lines look good and I didn't find any that were loose. I'll check the plastic line and jumper in the morning. Where is the lift pump located? Should I hear it kick on when you turn the key on? 

[carlotpilot]

if its pumping the filter dry or half its getting air somewhere before the fltr.

[Noland]

So I'm assuming that would mean the fuel line that runs between the filter and the tank. I'll check that one again but I didn't see any cracks and loose fittings. Someone told me there's a check valve at the first filter that could be the problem. Does anyone know where it's located and how it works?  

[carlotpilot]

possible cracked pu tube in tank check  that also

[Mack Technician]

Check the lines FJH was talking about, change the filters ( prefill ). Just fixed one of these issues and it was in fact that little plastic bleed off line from front of head. This one was 1998. I believe you also have no pump check valve (overflow) to hold fuel from returning to tank. You have a fixed office at main pump outlet. Fuel pump has to create pressure, by volume, by forcing fuel through small fixed office at the three way fitting leaving main pump on front side port out. No flow (or low flow) = No fuel psi. Any air leaks let fuel drop back to tank. Static vacuum holds fuel up in system. The transfer pump is mounted on the injection pump and drives off a cam lobe in main inj pump. There is no check at the first filter unless you have a Davco water separator.......which would be GREAT to have in this case. Good Luck!!

[Noland]

Do you know where I can get a schematic of the fuel system? 

[Noland]

I checked all the lines and they all seems to be okay. Got in tried to crank it and nothing. Sprayed either and cranked for a second then shut down. Done that several more times and it still wouldn't crank. Finally after bleeding air from the lines and loosening the injector tubes it cranked and ran all day. The tanks where about 1/4 to 1/3 full so I filled them up to about 3/4 full and ran the rest of the day. The next morning it cranked right up with no problem. I had 2 different people tell me there's a ball type check valve in the secondary fuel filter and that you should be able to take the filter off and see the ball dropped down sealing off the tube off. Looked for the little ball and didn't see anything. Seems like it cranked fine with 3/4 tank of fuel. Could be something going on there but won't know for sure until it cranks after sitting a days. 

[Rob]

Seen more than a few broken fuel pickup tubes in the tank on the 100+ gallon CH tanks. Which of the two fuel filters was not completely full? Primary will go down starving the engine out if inlet line is compromised from the tank or the pickup tube integral to the tank is compromised. If secondary was low but primary was full, air leak is after primary but prior to secondary filters. Regardless, filters being low are a direct indication of a compromised fuel system.