governor problem?

[fabricator]

Important... are you certain you are on the correct stroke? Try spinning it through several complete cycles and try again... fuel must shut off at some point unless the plunger is stuck or incorrectly installed/machined. Stranger things have happened!

I can send you another pump or pump parts to help if you want to experiment with it that way.

dieselgman

On second thought I think a new pump might be a good idea, that way I can compare the two to see if there is anything different, I suspect the piston but I can't be sure without something to compare it to.

[dieselgman]

OK, that sounds like one route that can be helpful for you. I did not hear from you whether or not you confirmed which stroke your engine was on when you could not get the fuel flow to stop. I have done spill timing on Listers hundreds of times and they fool me every once in awhile.

dieselgman

[Ronmar]

The inlet port must be sealing at some point, because if it didn't it would never build any/enough pressure to pop the injector...

Here is a silly question, did you get the 19 degree mark on the correct side of the TDC mark?  When turning the flywheel in the running direction, the 19 BTDC mark should pass the pointer about 3.5" before the TDC mark does...  TDC is with the flywheel keyway pointing straight down and both valves closed as you mentioned.  On my 6/1 the IP plunger first starts to move upward at about 90 degrees BTDC and stops about 45 degrees After TDC...  IE: the IP plunger only moves in relation to TDC on the compression stroke...   

[fabricator]

Yep, I double confirmed it's on the right stroke, key pointing straight down both valves closed, and yeah the 19 degree BTDC passes the pointer before it gets to TDC, I'm gonna mess with it some more once I get a little heat out there, it's 28 degrees F here this morning, we have been luck though, no snow on the ground.

[fabricator]

I got my spill timing perfect finally, then I switched out my plastic fuel lines to hard lines with flare fittings, and still no joy, still getting a variation in speed, not as bad as before but ever five minutes or so it slows down 50-60 RPMs, when this happens the rack moves to almost wide open for a second or two to recover.
I can't understand how it could be fuel starvation, when I take the banjo fitting off the pump fuel pours out, I'm totally stumped.

[Ronmar]

Well do you have a test tank you could try?  Is your current tank vented freely?  A cyclic RPM shift might indicate a buildup of vacume somewhere that slows fuel delivery.  The rack shifting might work this out till it happens again...  A test tank with a inline filter would at least eliminate fuel flow as a source...

[fabricator]

Yeah, I can try that, I got lots of tanks around here, I also think I'm gonna take the muffler system I have off, maybe too much back pressure, I'll try one at a time.

[akghound]

Water in the fuel??

[XYZER]

I got my spill timing perfect finally, then I switched out my plastic fuel lines to hard lines with flare fittings, and still no joy, still getting a variation in speed, not as bad as before but ever five minutes or so it slows down 50-60 RPMs, when this happens the rack moves to almost wide open for a second or two to recover.
I can't understand how it could be fuel starvation, when I take the banjo fitting off the pump fuel pours out, I'm totally stumped.

Does it slow down then the rack opens or does the rack open slowly while it slows down? "when this happens the rack moves to almost wide open" If it is going to open after it slows down it has a problem in the linkage a noted issue area. The linkage has to be broke in with the rings Oh when it slows down have you grabbed the rack and tried to speed it up?  

[fabricator]

@ Akg, it's pure, clean, dry, biodiesel
@ xyz, It starts to slow down then the rack responds.

[cgwymp]

Well do you have a test tank you could try?  Is your current tank vented freely?  A cyclic RPM shift might indicate a buildup of vacume somewhere that slows fuel delivery.

That's an interesting thought. Fabricator, what is your current tank setup? Before going to the trouble of changing tanks, could you try simply running it with the cap removed to see if the problem disappears?

[Ronmar]

@ xyz, It starts to slow down then the rack responds.

That is not right...  The rack should vary smoothly WITH changes in RPM.  Possibly something hanging up somewhere in the linkage.  I had to work on the yoke assembly at the top of the 90 degree bellcrank on mine to get it to slide smoothly thru the bellcrank arc of travel.  The round rod on the yoke and the hole it fits in on the bellcrank, were a rough sloppy fit.  I almost bored it out and put in a bushing, untill I was able to smooth it enough to get the yolk to slide smoothly.  I put a VERY light spring across the union to control the slop...  I have a throttle pull cable off of a weedeater I have set aside to experiment with replacing the whole linkage with a second small spring on the rack itself to keep the entire process smoothly in tension.  Like many things, just havn't got around to it...

[dieselgman]

Fab, are you able to post or email some pics of your linkage pieces? A bent upper linkage has caused us some problems similar to yours before.

dieselgman

[XYZER]

The linkage has to be broke in with the rings

Oh when it slows down have you grabbed the rack and tried to speed it up?

I have reworked bushed machined bent tweaked my linkage and it never worked perfect from the start. I always had to oil wiggle and babysit to get things settled in. After time and it breaks in it works like a fine Indian watch....lol. A well documented common problem. To remove the fuel supply issue the next time it starts to slow down grab the rack and force it some fuel. If it speeds up it is not a fuel issue.
Dave

[fabricator]

Yeah I can post some pics, maybe a little video, I already tested the fuel flow, I just took the fuel line off the filter and turned the banjo fitting straight up, adapted a chunk of 3/4 vinyl tube to the fuel line and filled the tube, same old thing, it runs smooth till it gets hot and then starts the high low thing, right now I'm checking valve tappet clearances.