Primerdimer Posted April 11, 2021 Report Share Posted April 11, 2021 Hey guys, I’m sure this is covered somewhere and I’ve researched a bunch, just nothing that is solving my issue. I have an L16 in 521 and a couple days ago the idle seemed a tad rough, then it wouldn’t start after shutting it off. I narrowed it down to fuel. I connected a fuel line to pump inlet and the other end was put into a gas can. Turned it over and no gas coming out of pump outlet. So, I replaced the pump and cleaned the fuel filter (which wasn’t too bad). Then I blew high pressure air backwards thru the line and heard it bubbling in the tank so no clogs there. I’ve been turning it over and over but no gas is getting pulled into the fuel filter. I even used some starting fluid and got the engine to run for a couple seconds but still no fuel being pulled. any ideas? thabks Quote Link to comment
Primerdimer Posted April 11, 2021 Author Report Share Posted April 11, 2021 I did the same thing with the new pump installed: attached a hose to the pump inlet and fed into a water bottle of gas... still not pulling any fuel tho. Quote Link to comment
datzenmike Posted April 11, 2021 Report Share Posted April 11, 2021 STOP! DON'T RUN ENGINE Take the valve cover off and check out the eccentric in front of the cam sprocket. If the head has been off and the sprocket bolt wasn't tightened enough and has come loose the eccentric will slip. Find out before you run the engine again. If that bolt backs out from running it and falls out the cam sprocket will fall off the cam and the timing chain tensioner will fall out. The damage could be bent valves and chewed up timing cover and more. Quote Link to comment
thisismatt Posted April 11, 2021 Report Share Posted April 11, 2021 So no fuel is coming out the pump outlet with the new pump, or did you just hook the new pump straight to the carb? Quote Link to comment
datzenmike Posted April 11, 2021 Report Share Posted April 11, 2021 Sudden loss of fuel. Filter and pump replaced and line blown out Still no fuel. Check the eccentric ! Quote Link to comment
banzai510(hainz) Posted April 12, 2021 Report Share Posted April 12, 2021 (edited) take the pump than pump the arm by hand!!!!!!!!!!!!!!!!!!!!!! take off the gas cap idle rough could just need a timing light and set that to say 10deg btdc maybe idel jet is getting plugged cut open the fuel filter and see how dirty and rusty it is. 521s esp in wet and dirty areas need to be swapped out more often dirt get down fuel neck in tank Edited April 12, 2021 by banzai510(hainz) Quote Link to comment
Primerdimer Posted April 12, 2021 Author Report Share Posted April 12, 2021 (edited) Thanks everyone for your help. So I figured out my issue was that the pump arm was not sitting on the eccentric, but below it. From turning it over so many times, the arm kinda gouged the eccentric, but not too bad. I hooked it back up and it started up and ran no problem. THEN, while driving to work, I suddenly lost power and bogged down. I pulled the hose off the pump outlet and turned the motor over and no fuel pumped out. Is it possible the arm slipped off somehow? I never took the head off so i don’t think the eccentric is loose and my fuel looks super clean in my fuel filter (I have one of those glass ones with replaceable filters). I don’t have tools on me right now so I can’t do anything until later tonight or tomorrow. Thanks Edited April 12, 2021 by Primerdimer Quote Link to comment
datzenmike Posted April 13, 2021 Report Share Posted April 13, 2021 Question. Is your pump bolted directly to the head? or is there a 1/4" plastic pacer between? The pump arm does not usually come off the eccentric like that ever. Quote Link to comment
thisismatt Posted April 13, 2021 Report Share Posted April 13, 2021 Could be the wrong pump. Did you carefully compare the arm and pivot location to the old one? Quote Link to comment
datzenmike Posted April 13, 2021 Report Share Posted April 13, 2021 The original pump didn't pump either. Also if the spacer is left off a factory pump the arm is gouged by the eccentric. Quote Link to comment
thisismatt Posted April 13, 2021 Report Share Posted April 13, 2021 49 minutes ago, datzenmike said: The original pump didn't pump either. Also if the spacer is left off a factory pump the arm is gouged by the eccentric. Well, that could have been the old pump failed Quote Link to comment
Primerdimer Posted April 13, 2021 Author Report Share Posted April 13, 2021 14 hours ago, datzenmike said: Question. Is your pump bolted directly to the head? or is there a 1/4" plastic pacer between? The pump arm does not usually come off the eccentric like that ever. The spacer is there. I’m not sure that the arm came off, I was just speculating since I don’t have fuel pumping again.. 12 hours ago, thisismatt said: Could be the wrong pump. Did you carefully compare the arm and pivot location to the old one? I did compare them, but prob not careful enough. I know the arms didn’t have identical shapes but seemed to end up in the same location as far as the eccentric goes. When I get off work today I’m gonna pull the valve cover and check it out. Thanks again Quote Link to comment
d.p Posted April 13, 2021 Report Share Posted April 13, 2021 14 hours ago, Primerdimer said: Thanks everyone for your help. So I figured out my issue was that the pump arm was not sitting on the eccentric, but below it. From turning it over so many times, the arm kinda gouged the eccentric, but not too bad. I hooked it back up and it started up and ran no problem. THEN, while driving to work, I suddenly lost power and bogged down. I pulled the hose off the pump outlet and turned the motor over and no fuel pumped out. Is it possible the arm slipped off somehow? I never took the head off so i don’t think the eccentric is loose and my fuel looks super clean in my fuel filter (I have one of those glass ones with replaceable filters). I don’t have tools on me right now so I can’t do anything until later tonight or tomorrow. Thanks Why would you need to take the head off to see if the eccentric was loose? Simply taking the valve cover off would tell you that. If it were me I would just buy a new fuel pump and eliminate it as the cause. Quote Link to comment
banzai510(hainz) Posted April 13, 2021 Report Share Posted April 13, 2021 Like I said before pull the pump and pump it by hand. If it works there then its a gap or eccentic issue. this is a simple fix. Im not getting it. fuel pumps has a spacer inbetween. does this do this when full tank or does this at a lower level? Quote Link to comment
Primerdimer Posted April 13, 2021 Author Report Share Posted April 13, 2021 7 hours ago, d.p said: Why would you need to take the head off to see if the eccentric was loose? Simply taking the valve cover off would tell you that. If it were me I would just buy a new fuel pump and eliminate it as the cause. I understand that, I was saying that because someone said that it might be loose if I removed the head at some point. And this is a new pump. 6 hours ago, banzai510(hainz) said: Like I said before pull the pump and pump it by hand. If it works there then its a gap or eccentic issue. this is a simple fix. Im not getting it. fuel pumps has a spacer inbetween. does this do this when full tank or does this at a lower level? ok so I just went over to the truck (across town where it broke down) and pulled the valve cover. The fuel pump arm came completely disconnected and fell down by the timing chain. The spring too. I’m gonna go over with a retractable magnet and fish them out. Wondering what may have caused this? I’ll have to compare the arms, and maybe just use the arm off my old pump. Do you think the gouge in the eccentric could have pushed the arm around enough to knock it off the pump? Quote Link to comment
datzenmike Posted April 13, 2021 Report Share Posted April 13, 2021 Stock original Hitachi pumps don't fall apart like that. Maybe the first one was a replacement too??? I doubt that the replacement pump is an original Hitachi. Was the original pump like this?.... You should still have it. Never throw away stuff and never an original part. Look like this?... Quote Link to comment
Primerdimer Posted April 13, 2021 Author Report Share Posted April 13, 2021 5 minutes ago, datzenmike said: Stock original Hitachi pumps don't fall apart like that. Maybe the first one was a replacement too??? I doubt that the replacement pump is an original Hitachi. Was the original pump like this?.... You should still have it. Never throw away stuff and never an original part. Pretty sure it wasn’t original. Quote Link to comment
Primerdimer Posted April 13, 2021 Author Report Share Posted April 13, 2021 Here is the arm comparisons... apparently the arm didn’t just come disconnected, but snapped in half... the new, broker arm is on top of the old one. Quote Link to comment
datzenmike Posted April 13, 2021 Report Share Posted April 13, 2021 What about the firsat one that stopped pumping??? Is that the one that just fell apart? If so these are obviously crap and the second one followed the first. Quote Link to comment
datzenmike Posted April 13, 2021 Report Share Posted April 13, 2021 I'm trying to find out if both pumps were not original Hitachi pumps. Quote Link to comment
Primerdimer Posted April 13, 2021 Author Report Share Posted April 13, 2021 (edited) 16 minutes ago, datzenmike said: What about the firsat one that stopped pumping??? Is that the one that just fell apart? If so these are obviously crap and the second one followed the first. The first one just stopped pumping and that is the one in the pic I posted... The second one fell apart and looked like the pump in the upper-most picture you posted.(with the bolts holding it together). Is there somewhere that sells hitachi ones? Edited April 13, 2021 by Primerdimer Quote Link to comment
d.p Posted April 13, 2021 Report Share Posted April 13, 2021 they have Niki ones on ebay and I am using an airtex which was recommended by another member here. https://www.amazon.com/gp/product/B000V81FHI/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 Quote Link to comment
thisismatt Posted April 14, 2021 Report Share Posted April 14, 2021 Didn't use the spacer and overextended the arm? Quote Link to comment
banzai510(hainz) Posted April 14, 2021 Report Share Posted April 14, 2021 i HEARD OF THESE NEWER PUMPS THE ARMS BREAKING OFF. THE ecentric I would swap out as it has the burr in it. migh be the issue of the 2nd one breaking. catching the edge. Quote Link to comment
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