How many pumps r21 fuel pump are enough

[bjp447]

I just got thru changing the fuel filters on the yanmar 20hp diesel on my 98 R21, This was the first time I have done it. At any rate I did the change, added diesel to the primary filter and started pumping that little lever on the fuel pump. 500 times didn't do anything, so I tried another 500, still nothing. took the input hose off and sucked some diesel to it, pumped some more still nothing. Got a suction device, pulled diesel to the input of the pump, pumped the lever some more , still nothing at the bleeder screw at the fine filter. Took my suction device to the output of the fine filter , got diesel pulled to there, tried the lever again to clear the second bleeder screw, nada. Cranked the engine, while playing with the bleeding screws and it finally started.
I am wondering how do I know that the pump on the fuel pump is working with the lever, how many times do you need to pump that lever to get fuel moving, anyone know, kinda, approximately? I must have pumped it over 1500 times, I counted. I did try turning the crank a 1/4 turn to be sure the lever wasn't on a ?. I hate to replace the pump if I am doing it wrong, but I would like to replace the pump if I need to.
As a side note , in trying to figure out how to pull the diesel without sucking on a hose, I got my West Marine oil change vacuum canister, taped a nozzle to the end and stuck that in the hose ends and bleeding screw holes to pull the diesel, worked great.
Now a new impeller and I will be in the lake next week.

 

[SGIDAVE]

I just got thru changing the fuel filters on the yanmar 20hp diesel on my 98 R21, This was the first time I have done it. At any rate I did the change, added diesel to the primary filter and started pumping that little lever on the fuel pump. 500 times didn't do anything, so I tried another 500, still nothing. took the input hose off and sucked some diesel to it, pumped some more still nothing. Got a suction device, pulled diesel to the input of the pump, pumped the lever some more , still nothing at the bleeder screw at the fine filter. Took my suction device to the output of the fine filter , got diesel pulled to there, tried the lever again to clear the second bleeder screw, nada. Cranked the engine, while playing with the bleeding screws and it finally started.
I am wondering how do I know that the pump on the fuel pump is working with the lever, how many times do you need to pump that lever to get fuel moving, anyone know, kinda, approximately? I must have pumped it over 1500 times, I counted. I did try turning the crank a 1/4 turn to be sure the lever wasn't on a ?. I hate to replace the pump if I am doing it wrong, but I would like to replace the pump if I need to.
As a side note , in trying to figure out how to pull the diesel without sucking on a hose, I got my West Marine oil change vacuum canister, taped a nozzle to the end and stuck that in the hose ends and bleeding screw holes to pull the diesel, worked great.
Now a new impeller and I will be in the lake next week.

Hello BJP,

I don't know what's wrong with your priming lever. On my 3YM30, the lever usually gets fuel bubbling out the bleed screw within 5-10 strokes.

/dave

 

[harry ames]

My classic 21 18 hp lever gets the diesel up there in abut 10 to 15 pumps. Now that the fuel is up there, I'd pull the top bleed off the fuel filter one more time (the filter on the engine) and see if it is pumping ok with the lever. If so, I'd imagine you have nothing to worry about. Also, my boat has two separate fuel valves associated with the diesel tank. Both have to be on.

 

[bjp447]

Thanks
I am going to have to pull the pump, the lever moves with very little resistance and I can pump that thing until I am blue in the face and nothing happens. I appreciate it.
Anyone know of any little tidbits you need to know before pulling the fuel pump? Gotta love those little diesels!
Bruce

 

[Capt’nKarl]

It might have to do with the engine cam position. If the cam is not in the right position you will not be able to prime the injector pump. Try a 1/10 sec start or turn the cam shaft manually. This should help.
CaptnKarl

 

[bjp447]

thanks, I tried turning the engine 1/4 turn, than a couple more times a little less a little more, didn't make any difference.
I will let you know what I find when I take it off
Thanks again

 

[JohnH]

Are you sure that you are pushing the lever hard enough at the bottom of its throw range? My past experience with a 2-cylinder Yanmar diesel was that, through most of the throw range of the priming pump lever, there was essentially no resistance and it accomplished nothing toward moving fuel. Only the last small amount of the total throw range actually pumped fuel, and it required significantly more force on the push. It was very easy to pump forever and accomplish nothing until I (accidentally) discovered how to use the active portion of the lever motion.

 

[bjp447]

Well JohnH your my hero, I bet that lever didn't move more than another 16th of an inch when I really pushed it at the end, but that 1/16th of an inch moved the diesel. That is the tidbit I was looking for, thanks again