3116 losing prime

97' 3116 LMTV. If I pump primer bulb, it takes about 10 pumps to get "solid" feel. Go to crank up and get tons of smoke for 30 seconds, up to 45. I usually only push the starter about 5-10 seconds max. It will occasionally sputter through the whole 30-45 seconds before finally clearing up in a nearly instantaneous burst. It will die sometimes during the start I will hit the start again for another 5-10 second round and wait again. It has not been very cold lately, so I have not used the ether lately. I did try the ether once and it did not help. I do not see any fuel leaks anyplace. I read on another thread about the bulb primer losing prime due to air leak. I have checked the connections and do not see any obvious line cracks. Is there a way to rebuild the primer bulb part and see if that fixes the issue? Or should I lean towards check valves not holding the fuel? Also, once its warm, it will restart easily, but after a few hours, its back to Cheech and Chong smoking.

* also, I checked the water separator and got maybe a tea spoon of water, but that was it.

the primary filter housing has an air leak. usually from the primer bulb. my buddy at the cat dealer said the best thing I could do was replace that housing with a non primer housing than add a cat primer pump.

jkcondrey said:

97' 3116 LMTV. If I pump primer bulb, it takes about 10 pumps to get "solid" feel. Go to crank up and get tons of smoke for 30 seconds, up to 45. I usually only push the starter about 5-10 seconds max. It will occasionally sputter through the whole 30-45 seconds before finally clearing up in a nearly instantaneous burst. It will die sometimes during the start I will hit the start again for another 5-10 second round and wait again. .... I do not see any fuel leaks anyplace. I read on another thread about the bulb primer losing prime due to air leak. I have checked the connections and do not see any obvious line cracks. Is there a way to rebuild the primer bulb part and see if that fixes the issue? Or should I lean towards check valves not holding the fuel? Also, once its warm, it will restart easily, but after a few hours, its back to Cheech and Chong smoking.....

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Ok... therein lies the problem. You're brain has not switched off the petrol engine way of thinking. Throw that out the window cause it will do nothing but confuse you. Diesel is a different animal. You will most likely NOT EVER see a fuel leak in the system of a diesel engine that runs... cause the leaks is air being sucked in not fuel out.

Otherwise the start up..... If it has been in the 40's there at start up this sounds pretty common for a not pristine, has lived a life of some work; CAT 3116. Not sure about the norm feeling of the primer bulb. Maybe shoot a video of start up (let us know temp at the time) so we can tell if it is around normal start up.

That truck has a bad suction line before the primer pump from the way it was acting. I would replace the primary filter first and start on transduction lines

The line from the fuel tank to the primer pump is a common culprit. Parker shop can make one. The hand primers also get dry inside and crack and suck in air.

ours did the same thing, it was the hand primer like Superman just said

Seth

Adventure Driven said:

ours did the same thing, it was the hand primer like Superman just said

Seth

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Seth, did you rebuild the primer pump or use something else?

You have to replace it.

We replaced the entire unit

Seth

jkcondrey said:

Seth, did you rebuild the primer pump or use something else?

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