Freestyle Please help. Air in fuel lines.

[Sasquachcrap]

Ok so a few weeks ago I started having an issue with the duel 44 carbs that I had recently rebuilt. I have done away with the selector switch and am running 2 pickups and each carb is separate. The ski started running poorly and I pulled the good off to see very little fuel in the fuel filters. ( which are also new). When I would crank it I could observe very little fuel filling the filters and every now and then a slug of air would enter the line. Hence the poor running. I pulled the carbs off and want through them again thinking that the pumps might be acting up but every thing looked good and went back together fine. I thought I had it fixed now 2 tanks later same issue. Any suggestions?

 

[amitchell]

Check those clear plastic valves on the pump side for cracks or creases. Check pulse and pickup lines for cracks. Crank over with palm covering carb and see if it sucks fuel.

 

[Sasquachcrap]

Will do thanks. Also I have tested the motor for air leaks and it will hold pressure pressure used to 12 pounds. Only lost 2 or 3 pounds over like 5 hours. But the motor runs away on the stand. I am sure the run away condition is from the air in the fuel lines.

 

[Sasquachcrap]

I will check all that again but. All the lines are new only a few weeks old.

 

[OCD Solutions]

A little bit of air trapped in the filters is common but if you are seeing a slug like you describe, it has to be sucking air from somewhere between the filter and the tank. So, I would pull and inspect the fuel pickups in the tank. Did you modify the OEM setup for dual pickups or go with something aftermarket? Did you use cheap line that could possibly curl itself above the fuel level and suck air? Is there anything on the ends of the fuel line like weighted clunks to keep it at the lowest part of the tank at all times?

Brass clunks are preferred over the plastic fuel pickup/filters.

I get mine from Jetski Solutions
http://www.jetskisolutions.com/p61_fuel_pickup_clunk.html

 

[Sasquachcrap]

I modified oem and extended both lines to about the bottom. Besides that the tank is fulI, also pressure tested the lines from the bottom of the tank. It held 60 pounds before I blew a line off a nipple that wasn't ziptied. I pinched the line closed at the carb during that test. No air leaks around the filters or primer but I took the primer out of the equation last test with the same results.

 

[OCD Solutions]

I read that wrong anyways, the trapped air is getting pulled into the fuel line not getting pulled from the tank.

Are the lines going into the tank straight drops to the bottom? Did you cut them on a slight angle or are they squared off ? If square, there is a chance they are touching the bottom of the tank and sealing off under suction. We just discovered this on a friends boat last week. He had new lines as well and it ran for a couple weeks before it started acting up.

 

[Sasquachcrap]

They don't extend below the stock slosh sleeve.

 

[OCD Solutions]

Time to yank those carbs then. While they are off, check your reeds. A broken petal will scramble pulse signal.

 

[Sasquachcrap]

Yep I'll try and pull them tomorrow. Can you buy just the pump parts? Like the check valves and rubber plugs and gaskets? Or do I need to just buy a few more rebuild kits?

 

[OCD Solutions]

I believe Jetmaniac sells the individual parts so you wouldn't have to buy everything again. He also carries genuine Mikuni parts which are a bit more $ but well worth it IMO. Never cheap out on cranks and carb kits.

 

[Sasquachcrap]

Ill take that advice.

 

[naticen]

Don't know your carb experience, but the plastic valves come with ink on them to mark which side goes outward. Also, you can't punch a hole through those rubber pieces when installing them. I use a flat side of a wrench to push them through and then a bobby pin to make sure it is fully seated. There is a tool available for it if you want.

 

[Sasquachcrap]

I did it like this and it works amazingly compared to trying to push them through with a tool.

 

[JetManiac]

Shouldn't have to replace any new parts unless you damaged something during installation. Both carbs have the same problem?

Must be a mistake in your carb assembly.

 

[Sasquachcrap]

Yes it seems like both carbs have the same problem. I checked the tank check valve and its working correctly. I hope I did put them together wrong but it ran good for a tank at the beach untill my bilge quit working and I got a little water in the rear cylinder then I started having this issue. Cleared out the water and fuel problem remained. Got home tore down the carbs checked the reeds and every thing looked good put it all back together and now 2 tanks later I had a similar issue with the bilge, I blew a fuse and had a bit of water in the hull but none in the cylinders. I pulled the plugs to check. It would crank and run it just had a bad lack of fuel bog. Now at the house on the hose when you crank it and then rev it a little you can watch little air bubbles dance around in the fuel lines then it will run away and when that happens I shut it off immediately. Is there a carb assembly video floating around somewhere that I could reference?

 

[surfjunkie]

not being argumentative but just trying to understand. how would any issues with the carb cause air in the fuel lines before the carbs? wouldnt it have to be entering somewhere upstream from the carb? i am dealing with this same issue on a ski right now. only reason i know it has air bubbles is the previous owner installed the pretty yellow see through fuel line. i assume air in the line is uncommon but because ive never owned a ski with see through lines i would not know

 

[OCD Solutions]

^ That was kind of the point I was trying to make in my earlier post.

 

[naticen]

I was kind of wondering if it was appearing in the return line. Maybe pressurize the pulse fitting with a couple pounds to check it for a seal. But yeah, I don't quite get it either. I'd definitely do some checking on the carb before tearing into it

 

[Sasquachcrap]

I don't think it is really the air in the lines that is causing the problem now as much as lack of fuel pump power. When I watched the lines I can see the air bubbles just dancing around, when I rev the motor I see them move towards the carbs slightly. I used a vacuum pump to pull all the air out of the filters. We will see how long that lasts. Also I pulled the carbs and tested the pump nipple for pressure. I thought I had a leak so I pulled it apart and replaced the gaskets and the diaphragm, but when I retested it I found my pop off tester hose was leaking on the nipple so I put a zip tie on it. Still leaked. So I put another. 2 zip ties later and I am holding pressure on both carbs too. So now I'm thinking since I didn't have those lines Zip tied on. Do you think that the pulse signal is being lost from a poor seal? My lines are new and not hardened. But I don't know how much pressure and vacuum is created when the piston travels up and down. I'm going to try and reinstall the carbs with double staggered ties on each nipple and I will post the results.