fuel delivery/carb issue

[BarryMac]

Hopefully one of you can help me with my issue. Unfortunately I know just enough to get myself in more trouble then I am already in...

Motor is a BBC with what appears to be a Holley 650. Had the carb rebuilt and reinstalled this weekend. Boat will fire up and run smoothly at 800rpms and up, when I pull the throttle back to neutral it starves for fuel and dies, it wont restart unless I put the hand throttle half way down, it fires, runs good again until I go to neutral then the it dies.

Any ideas? Would the fuel pump have any thing to do with this? I am definitely getting gas to the carb because the fittings were a little loose when I reinstalled the carb and fuel was dumping onto the manifold when the key was turned to the on position.

I would like to try and fix it myself and not rely on a shop if I can, mostly because I want to learn more about it...

 

[cave]

Floats maybe. Maybe too much fuel BM. Flooding the system. Don't ever place your face right over the carb when checking anything out.

With the key on, air filter removed, peek into the carbs opening and watch for fuel to leak into the venturies. Another way is to pull a spark plug. If its soaked with gas then your flooding.

Also a small piece of debris could be blocking one or all of your primary jets inside your fuel bowl.

Also this same type of debris could be affecting your inlet Needle. Thats the needle that closes off your fuel supply to the bowls when the float is floating to the top of the inside of your bowl trying to cut off the fuel. It could be stuck in the down position.

Here is a good site for Holleys
http://www.holley.com/TechService/Library.asp

 

[djunkie]

I'd start with checking the floats also.

 

[jetboatperformance]

Hopefully one of you can help me with my issue. Unfortunately I know just enough to get myself in more trouble then I am already in...

Motor is a BBC with what appears to be a Holley 650. Had the carb rebuilt and reinstalled this weekend. Boat will fire up and run smoothly at 800rpms and up, when I pull the throttle back to neutral it starves for fuel and dies, it wont restart unless I put the hand throttle half way down, it fires, runs good again until I go to neutral then the it dies.

Any ideas? Would the fuel pump have any thing to do with this? I am definitely getting gas to the carb because the fittings were a little loose when I reinstalled the carb and fuel was dumping onto the manifold when the key was turned to the on position.

I would like to try and fix it myself and not rely on a shop if I can, mostly because I want to learn more about it...

Just curious who (reliable ?) rebuilt the carb? and what prompted the rebuild eg was the problem existant before , call me if I can help 805 466 4719 Tom

 

[BarryMac]

Just curious who (reliable ?) rebuilt the carb? and what prompted the rebuild eg was the problem existant before , call me if I can help 805 466 4719 Tom

Carb guys name is Rick Walker in Santee or El Cajon. My river neighbor says that people from all over the world send him from mild to wild and he's a genius? My neighbor uses Rick and I trust my neighbor so I yanked it to send off with him.

The original problem occurred over Labor Day weekend. Boat started and ran great as we headed in, the ride was between 10 and 12 miles running between 3k and 4k rpm. As soon as I hit the no wake zone the boat began to sputter, I tried keeping it running but I think that the carb flooded and it died. I couldn't restart so go towed to the dock. I looked at it with a couple of guys that are far more knowledgeable then I and they saw all of the gas on the manifold, that suggested to me a carb issue. I was going to have the carb gone through this winter anyhow because it had been on the boat for 10 years and never touched, so I figured this was the time to pull it off and have it looked at.

 

[cave]

Too much fuel Barry. You need to adjust your floats. If you hit any rough water you may have bent the tabs that your needle attaches too.

If your lucky you can adjust the float height by loosening the locking screw on the float adjustment. Thats the slotted screw on top of the bowl. Lossen that screw then turn the 5/8 nut right (Rity Tighty) to raise the float. Left (Lefty loosey) to lower the float. till gas stops coming out while the fuel pump is on.



Worse case, you need to remove the primary bowl. Drain it 1st Pick up a new removable bowl gasket set for you Holley 2nd loosen the slotted locking screw on top of the bowl just a tiny bit. Next Remove one of the primary bowls bottom screws that connect it to the carbs main body to drain the fuel out of the bowl. Now remove the 3 other securing screws that attach the bowl to the carb. Dont crack the gaskets around these screws. I would replace them now.

Once the bowl is off flip it upside down so the adjustment nut is now on the bottom. with the locking screw loose you can turn the 5/8 nut in (righty tighty) to lower This is actually raising the float!!! or Loosen the nut (Lefty Loosy) this will be raising the float bowl. (Actually Lowering it). What you want to see is 7/16" to 1/2" space between the top of the float to the top of the bowl. So when you flip the bowl upright the space between the bottom of the float and bottom of the bowl is between 7/16" to 1/2"
With your finger holding up the float, (this closes off the gas going into the carb) Blow into the inlet feed where gas goes into the bowl. You should not be able to blow air into it.

If the float goes all the way to the top your going to need to bend the tab that the needle connects to the float. Pretty easy once you know what all the parts are. The float has a tiny tab sticking out that the needle attaches to and is kinda locked in by a spring type devise. To remove the float itself, remove the bar that the float pivots on to one side. Be careful not to loose any of the small parts like the bar or needle and spring retention deal.With the float in the up position bend the tab just a tiny bit up. You may be able to do this with out removing the needle. Re install then re adjust like above instructions.

Put it all back together.

Now your ready to fine tune the adjustment with the 5/8 nut. turn the pump on, watch for leaks. if your not leaking remove the brass plug unless you have a site glass on the side. Adjust the float up until the fuel is just at the bottom of the site hole. turn the fuel pump off.Drain the bowl again. tighten everything up. then turn the fuel pump on and watch to see if the bowl fills up with fuel.

If your leaking right from jump, Raise the float Righty tighty till the it stops leaking. Test like above.

good luck.

 

[djunkie]

Barry, another thing that might help. I had a problem with my new motor with brand new carb. 2nd trip out I had a similar problem and the float was sticking. Tapped on the bowls and it cleared up. I called my engine builder and he told me that its becoming a bigger problem nowadays with carbed motors cause of the shitty fuels nowadays. Since then I've been adding Marvel Mystery oil to my tanks of gas and since have never had the problem again.

 

[BarryMac]

Too much fuel Barry. You need to adjust your floats. If you hit any rough water you may have bent the tabs that your needle attaches too.

If your lucky you can adjust the float height by loosening the locking screw on the float adjustment. Thats the slotted screw on top of the bowl. Lossen that screw then turn the 5/8 nut right (Rity Tighty) to raise the float. Left (Lefty loosey) to lower the float. till gas stops coming out while the fuel pump is on.



Worse case, you need to remove the primary bowl. Drain it 1st Pick up a new removable bowl gasket set for you Holley 2nd loosen the slotted locking screw on top of the bowl just a tiny bit. Next Remove one of the primary bowls bottom screws that connect it to the carbs main body to drain the fuel out of the bowl. Now remove the 3 other securing screws that attach the bowl to the carb. Dont crack the gaskets around these screws. I would replace them now.

Once the bowl is off flip it upside down so the adjustment nut is now on the bottom. with the locking screw loose you can turn the 5/8 nut in (righty tighty) to lower This is actually raising the float!!! or Loosen the nut (Lefty Loosy) this will be raising the float bowl. (Actually Lowering it). What you want to see is 7/16" to 1/2" space between the top of the float to the top of the bowl. So when you flip the bowl upright the space between the bottom of the float and bottom of the bowl is between 7/16" to 1/2"
With your finger holding up the float, (this closes off the gas going into the carb) Blow into the inlet feed where gas goes into the bowl. You should not be able to blow air into it.

If the float goes all the way to the top your going to need to bend the tab that the needle connects to the float. Pretty easy once you know what all the parts are. The float has a tiny tab sticking out that the needle attaches to and is kinda locked in by a spring type devise. To remove the float itself, remove the bar that the float pivots on to one side. Be careful not to loose any of the small parts like the bar or needle and spring retention deal.With the float in the up position bend the tab just a tiny bit up. You may be able to do this with out removing the needle. Re install then re adjust like above instructions.

Put it all back together.

Now your ready to fine tune the adjustment with the 5/8 nut. turn the pump on, watch for leaks. if your not leaking remove the brass plug unless you have a site glass on the side. Adjust the float up until the fuel is just at the bottom of the site hole. turn the fuel pump off.Drain the bowl again. tighten everything up. then turn the fuel pump on and watch to see if the bowl fills up with fuel.

If your leaking right from jump, Raise the float Righty tighty till the it stops leaking. Test like above.

good luck.

Thanks Jimmy, that's great information... :thumbsup

Barry, another thing that might help. I had a problem with my new motor with brand new carb. 2nd trip out I had a similar problem and the float was sticking. Tapped on the bowls and it cleared up. I called my engine builder and he told me that its becoming a bigger problem nowadays with carbed motors cause of the shitty fuels nowadays. Since then I've been adding Marvel Mystery oil to my tanks of gas and since have never had the problem again.

Dave, third time in 3 days I have heard MMO in your gas instead of a fuel stabilizer. How much do you add and can it be left in there for longer periods of time. Say 3 months while the boat just sits over winter?

 

[djunkie]

Thanks Jimmy, that's great information... :thumbsup

Dave, third time in 3 days I have heard MMO in your gas instead of a fuel stabilizer. How much do you add and can it be left in there for longer periods of time. Say 3 months while the boat just sits over winter?

I only use stabilizer if the boat is gonna sit for a long time. There may be other fuel additives out there that are an all in one but from what my engine builder told me todays gas is a lot different than the old days and carbs don't like it. On the bottle of Marvel it tells you how much to use per gallon. People have been using it for years. Marvel from what I know is basically just a lubricant. Helps to keeps the fuel system from drying out and will help keep floats in the carb from sticking.

 

[cave]

Barry, another thing that might help. I had a problem with my new motor with brand new carb. 2nd trip out I had a similar problem and the float was sticking. Tapped on the bowls and it cleared up. I called my engine builder and he told me that its becoming a bigger problem nowadays with carbed motors cause of the shitty fuels nowadays. Since then I've been adding Marvel Mystery oil to my tanks of gas and since have never had the problem again.

Good advice right there djunkie! Tap the bowl 1st Barry.

I use the boat all winter. It may sit for 2 weeks. Av Gas seams to keep better but I'll only do 50 50 for cost reasons. But I got to tell you, when I did the 1st blower motor the boat sat for almost 5 months and the fuel was still good.

 

[Sleeper CP]

Carb guys name is Rick Walker in Santee or El Cajon. at.

Rick knows his stuff.....nice guy.

reset the floats.

this is a BBC with a 650 carb?

S CP

 

[BarryMac]

Rick knows his stuff.....nice guy.

reset the floats.

this is a BBC with a 650 carb?

S CP

I will tap on the carb first to see if that works. If not guess I will have to go the route that Jimmy (cave) suggested.

Yes sir, 454 and what I believe is a 650. No real markings, just what other guys have had on their boats similar to mine...

 

[cave]

Wish I had gone. It be fixed in less than a hour.

Not the carb builders fault Barry. Its common to have to adjust these things. Its best you learn. Really its so easy once you do it.

The water is so rough here in the summer mid day that its like running a trophy truck to the beach. I once purchased a float and needle set that was spring loaded like the Off road set ups. No one really notices that I have to do this a few times a year, Adjust the needles tab on the floats. I dont shy away from the rough stuff. Its my high.lol But the boat will prolly need some glass work down the line. Its easy after you do it a few times.. The float adjustment procedure is super easy.

If this fails its a fuel pump issue. If you have a fuel pressure gauge, you'll see the pressure drop and know.

Good luck boss! Remember if you have to take the bowls off buy a set of the good removable bowl gaskets 1st.

 

[BarryMac]

Thanks for all of the info Jimmy...

I totally trust the carb guy on recommendation alone and definitely know that it's not his fault. I will try and tap on the bowl before I attempt the float adjustment, hopefully that will fix my issue...

 

[BarryMac]

UPDATE:

The carb came back rebuilt with the floats set by Rick Walker. It is still doing the same thing, it's hard for me to tell if it is starving for fuel and dying or getting to much and flooding out. Anyhow, I guess that my next step is replacing the fuel pump. I have heard that a fuel pump can either lose pressure and it will starve the carb or to much pressure and flood the carb? Fact or fiction?

Tom at JBP. Do you have a fuel pump? 454, 380hp. On the motor now is the original fuel pump from 10+ years ago, the mechanic at the boat shop told me that if I got that many years I am doing good, he says that they usually last between 3 and 4 years. Not sure about that but he's seen more then I have. I also need a bracket for my diverter trim pump. The plastic one broke the same trip my carb took a crap.

 

[Fury25]

UPDATE:

The carb came back rebuilt with the floats set by Rick Walker. It is still doing the same thing, it's hard for me to tell if it is starving for fuel and dying or getting to much and flooding out. Anyhow, I guess that my next step is replacing the fuel pump. I have heard that a fuel pump can either lose pressure and it will starve the carb or to much pressure and flood the carb? Fact or fiction?

If its flooding i would assume you would see black smoke out the exhaust on start up (even with water)

This may be a stupid question but did you set the idle and idle mixture screws? you said it works 800 and above great but under it dies, i would make sure the Idle mixture screws are set correctly before i started with the fuel pump.

just my .02

 

[BarryMac]

If its flooding i would assume you would see black smoke out the exhaust on start up (even with water)

This may be a stupid question but did you set the idle and idle mixture screws? you said it works 800 and above great but under it dies, i would make sure the Idle mixture screws are set correctly before i started with the fuel pump.

just my .02

No black smoke so it must be starving for fuel.

I assume that Rick Walker set the idle and idle mixture screws.

Last weekend after I reinstalled the carb I took it to the launch ramp and fired it up, it idled fine at low rpms for about 30 seconds before it finally died. I can get the boat to restart after pumping the gas a few times but it obviously wont stay running.

 

[Fury25]

No black smoke so it must be starving for fuel.

I assume that Rick Walker set the idle and idle mixture screws.

Last weekend after I reinstalled the carb I took it to the launch ramp and fired it up, it idled fine at low rpms for about 30 seconds before it finally died. I can get the boat to restart after pumping the gas a few times but it obviously wont stay running.

While he can probably set the mixture screws close i would make sure there set somewhere. If you not sure where to set them at least turn them all the way in (counting the turns) then back out the same to make sure there not full one way. (just a thought)


Will the boat idle out of water on the trailer? If so i would crank up the idle a bit and see if that helps. there would be no way he could tell what kinda load the pump will have on your set up. also a jet will idle much higher out of the water than in it.

 

[BarryMac]

Will the boat idle out of water on the trailer? If so i would crank up the idle a bit and see if that helps. there would be no way he could tell what kinda load the pump will have on your set up. also a jet will idle much higher out of the water than in it.

I haven't started it out of the water, afraid to do damage to the pump. It seems to idle really well, just starves for fuel. I am really leaning towards the fuel pump, if that doesn't fix it then it will go to a shop.

 

[cruzer]

No black smoke so it must be starving for fuel.

I assume that Rick Walker set the idle and idle mixture screws.

Last weekend after I reinstalled the carb I took it to the launch ramp and fired it up, it idled fine at low rpms for about 30 seconds before it finally died. I can get the boat to restart after pumping the gas a few times but it obviously wont stay running.

Look at the filter and the pump.

 

[jetinator]

Im gonna go with wrong metering block gasket or base plate gasket that is blocking the idle circuit.

 

[460]

barry

you might want to try messing with the idle mixture screws. if all you did was throw the carb back on and not tune that might be the issue. You might have to have someone help you but run the boat at idle and see if its dumping fuel. What kind of pump is on there right now and do you have a regulator? How does it run under way?

 

[BarryMac]

barry

you might want to try messing with the idle mixture screws. if all you did was throw the carb back on and not tune that might be the issue. You might have to have someone help you but run the boat at idle and see if its dumping fuel. What kind of pump is on there right now and do you have a regulator? How does it run under way?

Fuel pump fixed the problem. Bought it at the NAPA in Yuma. Good dudes that new what they were looking at.

 

[460]

Fuel pump fixed the problem. Bought it at the NAPA in Yuma. Good dudes that new what they were looking at.

Right on man.

Glad you got it fixed.

 

[cave]

That's good news Barry!

Nothing like loosing power on the Colorado. Hopefully your upstream when it happens.