4.3 LX surging

[cooter2506]

Biat in question is in signature. This boat is new to me. First time out this morning. Got up on plane FAST. Ran about 1/4 mile and slowed to a stop. WAited about 2 minutes, engine still runnning idling perfectly. Got up on plane again, ran about 45 seconds and then started to surge. Seemed like about half power. Slowed to a stop. Waited long enought to look at wife and say "What the H*LL" and got back on it and it got up on plane just as fast as before and did same thing about 45 seconds later. My idea is that it is losing fuel. So im going to check into the tank strainer and carb filter. It is a 4 barrel weber. Any other thoughts I can check I can check into. Thanks in advance. Also wanted to let you know it just had a tune up.

 

[Don S]

Re: 4.3 LX surging

Go to the adults only sticky and read the thread on how to check your boats fuel system.

 

[cooter2506]

Re: 4.3 LX surging

I started checking a few things until I go out and get the hoses and guage. I removed the fule tank pick up and found filter clear. I removed the antisiphon valve and blew thru the end that attaches to tank. Seems like I have to blow really hard to get it to open and when it does it seems spirty(lol). another words not a real smooth amount of air coming out. Sound normal or is it bad.

 

[JustJason]

Re: 4.3 LX surging

Theres a test for it.... involves a yardstick and some clear tubing with water.... but i don't have in front of me what it's supposed to open at and close at.
Is your tank above or below the engine/fuel pump? You may be able to do without.

 

[cooter2506]

Re: 4.3 LX surging

My tank is below my fuel pump.

 

[JustJason]

Re: 4.3 LX surging

then you don't need the valve

 

[BIGALF]

Re: 4.3 LX surging

The easiest thing first. Check the fuel screen in the fuel tank. If you can't get to it to remove try to blow high pressure into the fuel line to remove the stuff cloged in the line. Another way to check the tank is to disconnect the line from the tank and run an aux tank to to replace the existing tank and try that. If it works then it looks like the fuel in the tank or the fuel line in the tank is the problem.
Also check any in line filters.

 

[cooter2506]

Re: 4.3 LX surging

I found the test on line on how to check the antisiphon valve. I performed the test and it said you should put 25 inches of water in a clear hose and hook it to the tank side of the valve. I did that and it had a SMALL trickle of water come out. Had to fill it to 30 inches to get about half the opening of water come out. Im thinking that this valve is bad?
BIGALF I already had the pick up out and it was as clean as a whistle. removed fuel seperator and it has NO water in it all fuel. Checked all hose connections and fittings on fuel line for tightness. Was all ok. There is no filter on the carb. Im leaning towards a bad antisiphon valve. Can I drill the ball out or should I just spring for the $1.25 Hose bib. LOL

 

[JustJason]

Re: 4.3 LX surging

buy a barb.

 

[sleeper]

Re: 4.3 LX surging

I had one do something similar a while back. I think it was the float adjustment in the carb not letting the fuel bowl fill up enough. By the time the float was letting more fuel in the carb was already starving for fuel. Seems like mine didn't run 45 seconds though, only about 10-15 seconds before it would starve.

 

[cooter2506]

Re: 4.3 LX surging

OK I was planning on buying the barb. Jason do you think my test is showing a bad valve. In my thougts I should have had a stream of water out of it instead of a trickle. Im putting a barb on it anyway doing away with the antisiphon valve. Just curios about my results.

 

[sylv196sport]

Re: 4.3 LX surging

Hey cooter the im no pro but im having fuel/carb problems myself same motor and carb and just to let you know the seloc manual states there is a internal fuel filter inside of the carb goody goody

 

[cooter2506]

Re: 4.3 LX surging

Took boat ou this morning and it ran flawlessly after I changed the antisiphon valve to just a plain hose barb. Ran it for 1.5 hrs no problems at all thanks guys.