No fuel ????

[Flyer5]

Hi Duck! I wasn't challenging your conclusions, i was just bringing a point of information, as I had a different, but related scenario that enlightement of the fact would have saved me some heartache... the circumstance being that most don't realize that the FP pushrods are not all same size... and to complicate worse, the fuel pumps aren't same either.

On subject of fuel pumps... USUALLY the separator filter is BEFORE the pump, not after.

I don't think the filter separator would be under any great stress of subjected to a few psi of downstream pressure, but they're fitted with the filter's seal. If i we're the engineer designing it, i would have made it capable of safely withstanding both positive and negative, but I wasn't that guy.

As others noted above, the anti-siphon valve at tank is a minimum-pressure check valve... it's cracking pressure isn't much, but it is enough so that some pumps might not prime effectively... so if you have challenging results, don't let that scenario foil you.


Just stick a flat screw driver at the end of the rod and pry the rod towards the camshaft have someone bump or crank the engine. See how much it moves. Doesn't need much.
The lobe wear-pushrod length just doesn't seem right to me. Loosing 50 thou of that rod isn't a nightmare, but to lose enough lobe lift to cashew your fuel flow, means the hardened cam surface has been cut through.

I'm very good at destroying things, and I've flattened a whole row of valve lobes, but I've never worn through a fuel pump lobe on a camshaft... and this is why it just doesn't seem right. if it were me (and it is a genuine pita to do in most boats) I'd cut apart a junk fuel pump, fit the body onto the block with rod in place, and measure the actual lobe lift with a dial test indicator. If it really IS a flattened lobe, then the next concern, is the other 16 lobes on that camshaft, that are under significantly more severe duty than that fuel pump... they might be very close behind.

 

[duckhead69]

Dave I really appreciate all your input . Don't mean to come off as challenging you just merely reinstating what I have done. So to clarify I had problem few weeks ago totally agree never seen this happen either bent yes. But my problem is 1) I hooked a outboard hose to tank got good gas and flow from it. Then went to carb line hook up and did same pulled gas from tank.
2) so fuel pump new one on nothing pulled plate to get push rod out and above pictures show wear on cam side my pictures are labeled wrong. While I was there bumped motor over and not a lot of travel did not put a indicator on it. But I say .250 now only moves 10mm/ .397 But new pin was not significant enough to warrant the problem.
3) So I am putting a electric on my system is as follows fuel route tank to filter her I want to put pump and regulator then into water separator then into carb.
I want to know if I can push gas thru the separator rather than pull fuel . Will it leak being only the seal on outer edge not in threaded area.
Hope this make sense to you all
Thanks

 

[DaveKamp]

I have seen it done both ways. I would put it in same plumbing position as the stock pump, but my gut says it will PROBABLY be okay either way... there's only a few pounds of pressure there... just don't use a high pressure or non-marine unit.

The mechanical pump is an actual thing of genius... it's pressure is preset limited by the diapragm's spring, and the lever merely pulls against that spring. Because of this, that pump will actually cycle the diaphragm a dozen times to fill empty bowls, then it stops by virtue of the carb float being closed... fuel trapped by the carb float remains at pressure determined by the spring, while the lever waggles away doing nothing. A quarter inch of travel should be more than enough to keep even the biggest engine fed.

I really, really think the problem is hiding from you elsewhere. Wish I was there to help you sort it out, it's a two-guys-together Problem to troubleshoot.

Here's a crazy suggestion-

Get some hose and barb connectors. swap the fuel feeds between port and stbd, and see if the problem stays with the engine, or follows the feed. Getting into those pumps is not easy, this might save you lots of tears and sweat.

 

[duckhead69]

great advice Dave I will add when I bench tested the old pump could barley actuate the arm . I suspect the pump seized up causing my problem. Old pump is out and made block off plate gonna try it all out today fingers crossed. I will update
Thanks for the help Marty

 

[duckhead69]

OK so I put electric on it and the coast guard approved line that I bought could not keep it from leaking. Teflon paste blue black all fuel rated sealants no luck kept leaking. So I thought pushing fuel thru separator was the issue but it was not. I went old school bought brass fitting cut the steel original line redressed the end put rubber fuel line from there to brass fitting on separator . No leaks took out for 4 hrs Sunday no issues . I did dial fuel pressure back to 3 psi. Ran like a scalded dog no problems thank god. Just wanted to update

 

[Scott215]

Where was it leaking from. The filter housing

 

[duckhead69]

It was leaking from the compression fitting on hose I bought new that goes from carburetor to separator fitting. That is a male or concave compression fitting coming out of separator. The hose end is female compression convex. I tightened the dam nipple on separator so much it cracked the housing. I thought that was it when I saw it leaking under pressure.But no that comp fitting could not get it to stop. Then like my previous post thought that pushing gas thru the separator is why it was leaking. But like I say went ole school rubber hose old steel line no leaks runs like normal.Fingers crossed

 

[Bill Curtis]

Hope you installed the low oil pressure shutoff, too (as required by USCG).