The Oddy has a fuel return line in the system and there is a very low pressure check valve in the line.
When the float closes the fuel from the pulse pump simply dumps to tank.
This check valve is very very weak so there will likely be very little pressure to overcome the float valve and flood the system.
I believe it will be ok but can't guarantee it. Pretty sure you will be ok.

I also run Quantum electric pumps on two of my machines and there is NO return line in that set up. My brothers machine has a high flow pulse pump.
All work great.

NOTE: You must get 4.5 oz of fuel flow in 10 sec measured with a stop watch at idle. You WILL melt your piston if this is not verified.

Hint: AVGAS
CO

Welcome new guy.
The site is very slow so you have to be patient for answers.
You will find no better site on the entire internet for Oddy and Pilot info.
CO

On one of the machines it is.
On the other one it's feeding a 38mm flat slide.
The high flow pulse pump is also feeding a 38mm flat slide.

Side note: I actually bought 3 Quantum electric pumps. My plan was to run all three on electric pumps. Unfortunately one of the electric pumps was defective. Sometimes it would run and sometimes it would just stop. If you tapped it with a rock or a screwdriver it would start up again. Reading the reviews apparently it's hit or miss if these pumps come from the factory in perfect running condition. I will say that on the other two units they run flawlessly.
In my opinion if I was you I would just stick with the original set up rather than monkey around.
Also a very important note here. The stock pumps are 40 years old now and are junk. You MUST replace it. You MUST also verify the flow rate I mentioned above in this post. You have been warned.
CO

One other thing I would like to mention is that much of the plastic stuff on an oddy is now brittle.
One of the things is that check valve in the return fuel line. It's plastic and VERY brittle. It's delicate and you can't get them anymore.
If you bust it then you will have to make a check valve out of a ball bearing, very light spring and a drilled out piece of round stock that is tapped on each end for a hose fitting.
If you need new fuel line then make sure you slice the old line with a knife along the check valve nipple before you remove it and then use oil or Vaseline on the new line to push it onto the check valve nipple.
Don't get ramy --- you'll regret it.
CO

It means if you do not resolve fuel delivery to the carburetor your going to enter a nightmare that will haunt you.

The stock Odysseys had fuel pumps, the needle and seat in the carb is smaller due to the carb being pressure fed. If you use a carb off of something that was designed for gravity flow when the float level drops and the needle opens with a fuel pump the pressure it will over fill the carb before the float can react. This will create all kinds of issues.

The same applies when you turn a Odyssey or Pilot into gravity feed only it starves for fuel, simple things like the gas tank VENT might affect the fuel delivery, then SOME will naturally add a inline fuel filter in the gravity system, every filter has a flow rate.

If you notice on gravity fed bikes, trikes, quads etc the just had STRAINERS in the tanks to catch large particles the agitation of the tank kept the strainer free flowing unless your tank was really dirty or rusted then it would reduce fuel flow.

So canadian oddy's comment was not an attack it was just to add emphasis. Above I only touched on the surface of changing the fuel systems designs from pressure to gravity or gravity to pressurized there is so many other factors involved, humidity, temperature, gas to oil ratio, brand of oil on and on. canadian oddy learned the hard painful way.

Well I just logged in and seen this.
Hoser is correct ---- I was not trying to be a clown.
I'm an industrial millwright (retired) and in my trade we are not a politically correct group. I guess I just come across "wrong" to some people. It's just how I am and how almost all of my co-workers are, even at all of the different work sites and companies I've been at.

Hoser is also correct in pointing out at the fuel issue stuff.
I've spent a lot of money knowing what I know about these machines and I've learned the most off this site.
I've melt almost a dozen pistons before I figured it out and the sick part is, that when I went back and read one of the replies in my very first post on the issue, a commenter actually pointed it out but I missed it. Stupid me.

Now I'm going to take a shot at you about your post.


It's not in the manual. They left it out but if you have a Pilot (FL400) manual it's in there.

You can laugh if you want but most of these machines have been kept outside. One of the tell tale signs a machine has been out in the sun a long time is by looking at the kill switch. Many are orange in color. They are suppose to be red.
This also means things like the fenders have been in the sun and they will shatter as soon as you lightly hit something. If you look close you'll see all of the "stars" in the plastic. It has fractures everywhere.

Thanks for that info. I tried to get one of those when I busted mine many years ago and my local Honda dealer said they couldn't get it.

oohhhhhhhhhh
Yes I know the threads you have read now.
6oz in 10sec is lots but that also tells me you got a big electric fuel pump.
It's mostly likely not a Quantum but some automotive pump and you are trying to regulate the flow/pressure by bleeding it off with a jet.
That's difficult to get correct.
Also of note is that the Oddy electrical system is pathetically small. Electric fuel pumps use up a lot of juice. The Quantum is very low draw unlike an automotive pump. You may kill your battery.
I also now know why your question about an electric pump when I made my original comment.
You are heading down a wrong road.
Good Luck. Keep us posted.
CO

This conversation seems to have veered off slightly...

The Odyssey alternator puts out 160 watts @5k RPM. or about 13 amps. Plenty for a small fuel pump. even better if you swap out the original light bulbs for some LED equivalent then you shouldn't have to worry about it at all. Sounds like your current fuel pump will be fine. My Odyssey also has a drilled out main jet in the fuel return line. It works, but its not perfect for instance the fuel system loses prime every time it sits for any amount of time. Otherwise, with my trail riding, I haven't had any running issues.

There is a fair amount of information on replacing the stock carburetor.
The most common one I see suggested is a 35mm Keihin PWK Air Stryker. This I believe is a good all-around carb for most riding. However if you ride in the sand dunes you may prefer to go bigger, 37-40mm.
Usually you can stretch the stock intake manifold around the 35, sometimes Ive seen it done with the larger ones, but not my preference. You can get a larger intake manifold from https://oddballorv.com/search/atv-model-fl350r/?q=intake and no, they are not cheap but that's the rub with playing with a 40 year old, 1 year only, ATV.

As far as using another carb, I don't know a ton about them, But I believe you might be able to swap out the float valve seat with a smaller one meant for fuel pump applications https://www.jetsrus.com/index.html is a great resource for finding OEM carbs and carb parts/jets. You could probably reach out to them to find out if the carb you want to use has a float valve for fuel pump application or if it needs one.