CO at the bottom of this thread is another thread where you posted you were using fuel pumps off a polaris,what happened to those?

The Polaris pumps were rock solid for years. Now they're shyt to me.
I have six brand new out of the box pumps laying on my bench that are junk.
There are 4 new Chinese and 2 brand new Japanese laying there as ornaments.
I don't know what has happened to the quality of todays parts but they failed the flow test.
NO my pick up tubes are not plugged. I built a new fuel tank for the death machine (there is a thread on it). It has new copper line in it. It had 5/16" line and then I put 1/4" line in it because it thought the pumps didn't have enough pull. Still no go. I tried the pumps on other machines -- no pass test. I bought new reeds thinking that was the problem -- nope !. I tried a spare Engine sitting on the shelf -- NO mas !
So now I try electric ---------- ONLY one poofkaboom.
I am trying .
CO

Damn CO that's a lot of frickin fuel pumps!

Since the vacuum pumps are all crap I am experimenting on them.
If I find a solution I will post it.
Monkeyed around with one of them tonight. Don't know if it works yet. Off to work tomorrow .
Told the guys at work a few weeks ago that when this pair of boots wears out I'm fkn retired.
CO

This is quite interesting. Thanks for posting this Eric. The K&N site says that it self regulates between 1 and 2 psi. Had only a couple of reviews on Amazon but both 5 star. $64 on Amazon prime.

From the K&N site......

https://www.knfilters.com/81-0400-fuel-pump

CO I don’t know why I didn’t think of this before but they sell the rebuild kits for the 350 fuel pump,did you ever try those? And speaking of the rebuild kits,every time Ive seen a pic of inside 350 pump it just looks like a series of gaskets you replace,I took apart my 400 pump and it was not what I was expecting After seeing the pictures of the inside of a 350 pump.

I have actually never F'd around with and FL350 fuel pump. I just bought a new pump.
I know Randman and others have done rebuilds on them and were successful.
I also know from posts here that the FL350 pump was a bit tricky to put together for some reason.
The pump you have posted pics of seems to be very well built. I am impressed. Those look like real valves and not some kind of mickey mouse plastic flapper valve. That FL400 pump looks real and not some piece of crap. I suggest you try a rebuild on it. Looks worth it to me.
CO

EDIT: Actually what I have done with the Polaris pump that I am experimenting with is that I put a stiffer spring under the check valve. I noticed that when I blew into this pump the air came out the inlet side. Which should not happen if the check was holding. It now passes my northern hillbilly test so now I have to try it on an Engine with real fuel. Will try to do that sometime this week.
CO

I wouldn’t know how to rebuild it,and now I see why no one is selling a kit to rebuild it

Maybe you better send it to me for free .
CO

LOL,I'm not convinced mine's even messed up,we'll see.
I have a buddy who says he can rebuild it because he did his ody pump,but I don't think he knows what he's in for.
He posted some pics of his rebuild on the ody pump on facebook,I could send them to you if youre interested in trying to do yours

No I don't need the pics but thx.
My old original oddy pumps are way different than what you got there. That does look like a good quality pump to me. Make every effort to fix it. Never throw it out as you never know if you come across a kit for it.
CO

A little food for thought,
when you are doing the flow test with the electric pumps you are comparing it to what the pulse pump puts out at cranking speed, maybe 600-700 rpm?, with a pulse pump it is going to put out more flow at higher rpms, the E pulp is only going to pump that much no matter how much load you are putting on it or at any RPM, so how much fuel will it take when you are running up a sand hill under full load at high rpms. you may want to think about putting on an EGT gauge so you have a better idea of what is happening.

The electric pumps self regulate. They shut off completely once the system is pressurized if the Engine isn't running. Run very slowly at idle and faster as the demand increases. Appears to me that they run as fast as necessary to keep a constant 2 lbs. of pressure.

so what is the output if run wide open with no restriction?

I'm curious to see how much it flows when measured for 10 seconds

It flows 4.5 oz in 10 seconds.

I think the point of "will the electric pumps work" is kind of mute now.
TerryH has already indicated in his rebuild thread that there were already machines running with these pumps successfully and I have been on several rides with my machine that has an electric pump. Also I now have figured out the electrical problem with the death machine which also has an electric pump and will try to take it for a spin next week maybe.
My brothers machine which blew up also had an electric pump but it was faulty from the get go.
It gave trouble not starting up right off the bat and I had to smack it with a screwdriver or a rock to get it to go. Therefore we can't really count this one.
I will report when I take them out again but they do seem to work as long as they aren't faulty right out of the box. The online reports (most) were not positive though. The complaints seemed to be DOA or not lasting more than a year. So we know that if it suddenly gives trouble or is DOA then toss it.
On a side note here, my brother was really pizzd we blew up his Engine with this electric pump. He has bought another vacuum pump and I have to put it on for him.
They do work.
CO

Mechanical pump should output much higher than 4oz/10sec when the Engine is running at 5000-7000 rpm. That is what Kuma is saying.

None of these pumps, electronic nor mechanical, have a the capability to scavenge well. If you research pump scavenging you'll know what I mean. Basically its the effectiveness at pulling the fuel up the line BEFORE the pump. None of these pumps have a scavenge section, hence probably the reason why they struggle. This becomes very important if you are pulling the fuel against gravity. Option would be to install the pump down low, below the fuel level in the tank so that gravity can help feed the supply line of the pump. Once the pumps are primed, then flow goes fine, but still the pumps have to struggle with scavenging/sucking up the fuel. Pumps are better at PUSHING rather than PULLING unless they have a scavenge pump section.

Second note. Since I'm into jet skis I'll let you in on a little secret with them. They run a closed fuel system whereas there is no outward vent at the tank. Well, there is actually - but the pressure needs to be at 4psi for the tank to actually vent. This is so nothing explodes under the hood - lol. Skis also run a one-way check valve inward so the tank will never go under vacuum either. The BEAUTY of this system is, the mechanical pumps push the fuel back into the tank while creating a small pressure in the tank - which in turn aids in supplying fuel back out the tank again to the pump. This is an effective way to scavenge actually.

I thought of converting to a closed pump system on our machines, but that would require a ventless cap and/or a cap with a one-way vent. It would not be hard to do given the right fuel cap.

Install the fuel pump UNDER your tank and you'll see much better stability in your fuel flows.

I agree with this statement 100%

I mentioned I used to have an old Kawasaki zx6 that used the same type of electric pump, it was in fact mounted lower than the tank, so it never had to pull fuel, it only had to push it.

If the stock Kawi pump was able to feed a 600cc sport bike Engine with 4 carbs at 12k or 14k RPM, I suspect it will do just fine with a 350 2 stroke. The 1000cc Ninja probably ran the same pump.

Yes, that is my concern, the 4.5 at idle is simply a baseline to verify the pump is working correctly, it should pump much more at high rpms, it's fine for running around the block but if you try to run this for extended periods of time under load and high rpms I think you are risking damage.

https://www.highflowfuel.com/i-23900328 ... n8EALw_wcB

Any reason to not save money and use this pump instead? I'm assuming theres some differences here but I am not sure.

That's interesting. Don't see why it wouldn't work.

Being a cheap bastard I couldn't justify the $69 for the one you guys bought, but this one at nearly half price....pretty considerable.

I hope the 30 bucks you saved doesn't cost you an Engine.

Haven't pulled the trigger yet. I will check flow of course, and yes I recognize that these don't really have the best reputation yet.

I know I'm gonna sound like a broken record, but the Kawasaki pump has a great track record. I think 1993 to 2002 zx6 if you care to check the prices.