Anyone tried an electric fuel pump on a GP12R?

[red5]

Rebuilt the carbs. Changed the jets. Not sure what my issue is. IF I hit the primer it runs GREAT! I have two jobs and I am getting tired of fucking with this old ski. Think if I throw a low pressure electric fuel pump on it that the thing will run fine. I've done this with older 2 stroke outboards in the past.

I'll run a switched hot to the kill switch.


Anyone ever done this? I'll check for fuel leaks after install. Can you tell me a good place for a switch hot?

[K447]

The problem is just with initial engine start?

If you prime the engine with gasoline is then starts and runs properly using the carburetors?

[red5]

The problem is just with initial engine start?

If you prime the engine with gasoline is then starts and runs properly using the carburetors?

It starts with primer. then it dies. I can't keep fuel coming into the carbs.

[K447]

It starts with primer. then it dies.

I can't keep fuel coming into the carbs.

So the fuel pump to the carburetor is not actually pumping liquid fuel.

Or something inside the carbs is not able to deliver the fuel into the engine.

Sounds like some diagnostics is needed to determine what is going on.

[red5]

So if I keep pumping the primer it keeps going fine.

[K447]

So if I keep pumping the primer it keeps going fine.

That is telling you that the carburetor system is not running properly.

Which needs to be diagnosed and corrected.

The carburetor is responsible for delivering fuel in the correct ratio to the air flow going into the engine. As you apply throttle squeeze the air flow increases and the carb (when it is working correctly) matches that with fuel. These 2-stroke engines depend upon the carb doing its job properly.

Your carburetor is not doing its job. An electric fuel pump would be a hack method of attempting to avoid doing the diagnostics to determine what is actually going wrong and fixing it.

Figure out whether the existing (stock) fuel pump is not moving fuel or the carb is not using the fuel the pump is delivering.

[red5]

That is telling you that the carburetor system is not running properly.

Which needs to be diagnosed and corrected.

The carburetor is responsible for delivering fuel in the correct ratio to the air flow going into the engine. As you apply throttle squeeze the air flow increases and the carb (when it is working correctly) matches that with fuel. These 2-stroke engines depend upon the carb doing its job properly.

Your carburetor is not doing its job. An electric fuel pump would be a hack method of attempting to avoid doing the diagnostics to determine what is actually going wrong and fixing it.

Figure out whether the existing (stock) fuel pump is not moving fuel or the carb is not using the fuel the pump is delivering.

Tried to figure thsi out. Not having success. Time is ever so important. Can you think of any reason why I can't run a separate electric fuel pump? Thinking a 3-4psi connected to a switched hot.

[K447]

- any reason why I can't run a separate electric fuel pump?

Thinking a 3-4psi connected to a switched hot.

Because you have not determined what is going wrong. The factory fuel pump may be working correctly and the problem is something else.

The stock pulse driven fuel pumps may vary in fuel pressure as the engine revs on the water and the carb configuration (jetting, etc) is matched to the normal varying fuel pressure. Your electric fuel pump will have a different pressure and flow profile so it may mess with the carb fuel:air ratio, effectively requiring you to recalibrate the carb tuning.

All this is separate from the safety aspects of adding an electric fuel pump. You want the fuel pump to stop whenever the engine stops, even if the lanyard is still in place. The most important aspect is not wiring the fuel pump to run, it is configuring the pump to stop running in every scenario where the engine itself may stop.

The stock mechanical engine fuel pump always stops flowing fuel when the engine stops turning.

In addition the majority of the fuel hoses are under mild suction from the stock fuel pump so a minor leak merely allows air into the fuel hoses. With an external electric fuel pump some hoses are now under pressure and a minor leak could spew fuel into the enclosed hull while you are riding, creating a fire and explosion risk.

[Myself]

You're working 2 jobs.........pay somebody that knows what they're doing to fix it!

[Jonesyfxr]

The pump bodies can be corroded or your fuel pump diaghrams are not installed properly.

A common problem after rebuilds can be improper fuel line ranting. If you follow the schematic it kinda messes people up because it looks different than the way the lines should be routed.

[Jonesyfxr]

Mourning pump bodies were corroded so bad we had to sand them true.

[raiderteen]

Tried to figure thsi out. Not having success. Time is ever so important. Can you think of any reason why I can't run a separate electric fuel pump? Thinking a 3-4psi connected to a switched hot.

You cannot run a electric fuel pump on a carbed jetski because the internal fuel pumps are a variable pressure fuel pump. It sounds like you don't have the time to be doing this yourself, and possibly lacking knowledge on how these fuel systems even work. Best to take it to someone who does. As the old saying goes, "Buy once cry once". Same principle here.

If you insist on doing the repair yourself then you need to do a full rebuild on the carbs using GENUINE mikuni rebuild kits, probably wouldn't hurt to include new mikuni needle/seats. Then test pop off pressure once complete. The power valve engines use the MK-BN44I-YAM mikuni kits only for the carb rebuilds. With this kit you can use the new spring, as its the only one (and correct) in the kit.

Why did you change jets? Is this ski stock?

[WFO]

all good info... dont forget you may have a flapper door warped or main pickup tube in sender butting up against the cap. Also try bypass fuel selector to eliminate problems

[red5]

Bought this ski not running right. Took it to a buddy that used to build these things. It appears to have an aftermarket pipe (A cheap one like the stinger). Removed the choke and installed a primer. Gutted the air box, no restrictions, no baffles, just the cover, no hose running to the bow. Pretty sure this system has no cat converter. Removed the carbs, cleaned them and then installed a full rebuild kit on all 3 carbs. It didn't run right.

So I took the carbs off and I bought the actual mikuni carb kits. Pulled the carbs apart and left teh metal parts in a sonic bath over night. Installed the mikuni parts and I still have to pump the primer for it to run.

This sucks. I don't know how to set teh pop off pressure. And I don't think that is my problem. I'm not getting fuel unless I hit the primer.

Not sure where to look.

Had a similar issue on an old two stroke 120 HP outboard and I installed an inline fuel pump. Ran GREAT!

Guys I need to figure this out or I won't be able to use this ski for another year. We have one pwc shop in town and he is backed up for 6 months and wants at least a thousand freaking dollars to mess with it. I'm not going to do that. I figure this out here or next week I buy and updated fire extinguisher and run an inline pump. lol

Not getting fuel. Got any ideas what I can check? Please be very specific on how I check. Wish this bastard was diesel.

[K447]

- We have one pwc shop in town -

Where are you located?