701 runaway on first start up?

[Snguy1214]

Just swapped stock 701 that ran perfectly before I put it in another hull. I doubt I have any air leaks, marked all my fuel lines so I know those are good. Motor has been sitting on bench and I have a Home Depot 2” plug as the nose of my ski is covered and can only fill tank internally. I need the kit for that @JetManiac. Do I just have a bunch of air in my fuel lines, there is not fuel in them, primer also having trouble getting “primed”. Only ran motor on 2 different start ups pulled Laynard as quickly as possible and motor dies.

 

[Freakie]

pull the return fuel line off from the tank. Blow into the one way air vent valve which goes into the tank while you hold your finger over the return nipple on the tank....pressure will build up in the tank and prime the whole system . Once fuel starts coming out of the return line.....let it bleed out for like half a cup full of fuel......pour about a table spoon into each carb......start it.....if it runs for a bit and say after 10-20 seconds again does a runaway....you got an air leak or possibly a fuel pump issue.

 

[maxboost]

Anytime my motor ran away I couldn’t stop it with my lanyard. If it stops with lanyard it pry not terrible serious, maybe butterfly open a tad too far and being a tad lean? Maybe check/clean the jets. My opinion

 

[JetManiac]

Another way to prime fuel lines before first start up:

Press and hold stop button first (this kills ignition/spark), then press start and let motor turn over for a bit. It will not start due to stop killing spark. The motor turning over creates a vacuum and fuel pump tries to pump fuel. You will see fuel slowly filling the fuel filter. Let it sit for a minute. Repeat several times. Your primer should work afterward. Now start motor.

If should not runaway now. If it does, then you have other issues. Sometimes pulling lanyard/pressing stop will not stop a runaway, in that case, cover air inlet or exhaust outlet to smother it and stall motor.

 

[smoofers]

In addition to the above comments, double check that your butterfly isn't being held open by the throttle cable adjustment being too tight. The idle stop screw should be controlling where your butterfly stops, not the throttle cable.

 

[Snguy1214]

My favorite way to prime Carbs and Fuel System is to attach a (bicycle) pump to the Fuel Tank Check Valve (with a short hose) and pump a few strokes of air into the tank.

Remember, a properly installed working Fuel Tank Check Valve will only allow air INTO the Tank.

This will fill all the Fuel Lines and Carburetors completely.

A Mikuni Pop-Off Tester can also be used.

I am not using that round plastic fuel water separator thingy that the check valve was hooked up to, kept priming for a few mins and finally got fuel. I also only had about a gallon of fresh fuel because I probably will not ride for awhile, so that’s most likely not helping. I will blow into the return like suggested, i have carb tuned way fat, it’s getting there. Thanks for all the help!! You guys helped put a lot through this Project, can’t wait to ride this thing!!

 

[Freakrider]

I am not using that round plastic fuel water separator thingy that the check valve was hooked up to, kept priming for a few mins and finally got fuel. I also only had about a gallon of fresh fuel because I probably will not ride for awhile, so that’s most likely not helping. I will blow into the return like suggested, i have carb tuned way fat, it’s getting there. Thanks for all the help!! You guys helped put a lot through this Project, can’t wait to ride this thing!!

If it runs away again pull your lanyard and then full throttle, it will kill the engine and works like a charm.

 

[badvinny]

Or prime it like a mofo!

 

[Snguy1214]

Throttle is not open, checked that first... am not using that round plastic fuel water separator thingy that the check valve was hooked up to, kept priming for a few mins and finally got fuel. I also only had about a gallon of fresh fuel because I probably will not ride for awhile, so that’s most likely not helping. I will blow into the return like suggested, i have carb tuned way fat, it’s getting there. Thanks for all the help!! You guys helped put a lot through this Project, cant wait to ride this new beast of a hull.
I’ll let you know how it goes after I get off work.
I just capped off The 2” fuel line on the original tank, just wanna make sure that’s not causing any issues? And I def cannot keep prying the top rubber cap off every time I fill up, anybody know of any cost effective ways to make a screw on cap right there besides spending 200$ on a kit? Thanks again for all your help this site rocks

 

[AAlamo]

Are you looking for something like this? Cheapest way to make an internal fill tank. I used 5200 on the gaskets to make sure it seals.

 

[Snguy1214]

Are you looking for something like this? Cheapest way to make an internal fill tank. I used 5200 on the gaskets to make sure it seals.

Yes that is exactly what I’m talking about, thanks for the pics!
Still trying to get this dang fuel system primed. Could the fuel selector knob be bad? I did not swap that out as the hull has the stock one. It looks like I’m getting fuel in one line, primer is pumping fuel, but the return line I believe or the line on the left is not getting fuel, I also see nothing in the line with the filter on it going to the bottom nipple of the mikuni 44.

 

[Snguy1214]

Update....ski is running great on the hose. Will tune on trailer soon, but anyways whoever it was that said to make sure the carb was not being held open, bingo! It was...I disconnected the throttle cable and the arm moved way further down then I had originally thought!!! Atleast it was an easy fix. Thanks guys

 

[Snguy1214]

Update....ski is running great on the hose. Will tune on trailer soon, but anyways whoever it was that said to make sure the carb was not being held open, bingo! It was...I disconnected the throttle cable and the arm moved way further down then I had originally thought!!! Atleast it was an easy fix. Thanks guys

New update: now ski will only run when I give her a few pumps on the primer. The check valvenonnn BBC the tank is allowing me to blow air through both sides and it actually came apart when I was trying to pull the fuel line off of it. After I prime it it will start up and run five for a few seconds then dies. Compression is 150psi in ea. Cylinder. Obviously I’m not getting fuel....hmmm

 

[maxboost]

if It was sitting for a while I’d just take the cover off the carb and check make sure everything looks good. I bet pilot circuit is partially gummed up. Knowing pop off pressure is also good to know as well. Tank breather most likely isn’t your problem.