Rebuilt carb, set float, still flooding?

[dccordell]

I'm learning that apparently there is a science to rebuilding a carb and getting it to work just right. I'm working on a two-barrel rochester off a mercruiser 470. I tore mine apart again today and put the rebuilt kit in it. It had most of the parts, but I was short the throttle body gasket. Could use the old one though so no problems. The float looked like it was in good shape, didn't seem to be saturated. I used the new needle valve and seat that came in the kit. After putting the float back on, I used the merc manual specs to adjust the float level and drop. I got it dead on.

Now when I put the carb back on the motor and pump some fuel to it from the old electric fuel pump (because I'm having other issues with the mechanical pump), it just pours out from the top of the carb (see pic) and through the two venturis (not sure on the terms here). It seems like the float is sticking right? But it's all clean and new. Maybe I will have to adjust it so that it closes at a lower float height? What else may I have missed?

Red circle is one of the spots that fuel is pouring out, the other spots are down inside the throat.

 

[redjmp]

Re: Rebuilt carb, set float, still flooding?

Perhaps your electric fuel pump has too much pressure?

 

[Eric 3.7LX Alpha 1]

Re: Rebuilt carb, set float, still flooding?

Maybe too much pressure from the electric pump?

sounds like the needle isn't seated properly. I'm not sure on your exact set up but on my 4-barrel, the small wire that the needle valve is clipped into has to be on the float arm a certain way and not into the holes or it won't seat properly and flood. Here's a pic I found online showing the float and clip.

again... not sure if your set up is similar or not, just figured I'd throw out the idea.

 

[mnm01]

Re: Rebuilt carb, set float, still flooding?

I'd agree,mechanical pump would be low psi(5-8) too high a pressure and it will lift the float off the seat

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Perhaps your electric fuel pump has too much pressure?

That's possible, but it really shouldn't since the guy that I bought the boat from had apparently been using the electric pump for a while. I understand the pump shouldn't be running while the engine isn't running, but even just to turn it on for a second before I begin cranking the motor it will start flooding out of the carb.

I actually used the elec. pump while the motor was still in the boat to crank it and it actually ran like that and didn't flood the carb... now that I have the motor out and trying to fix it, it's acting up.

I don't plan to use the electric pump in the boat at all, just using it now while I work on the carb and the fuel pump. I know it's all going to come together sooner or later! :redface:

Thanks for the help! Yall are probably tired of hearing from me.. haha

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Thanks for the diagram Eric... mine isn't quite the same but I'll keep that in mind when I take it apart again. In the original setup, the needle didn't have a wire clip but the rebuild kit came with one and I wasn't sure how to put it in. I'll check to see if I have it in the right way.. I'll let yall know. Am I correct that it must be flooding if the fuel is being poured out like that in those spots?

Any other ideas?

 

[CobiaXL]

Re: Rebuilt carb, set float, still flooding?

The wire clip helps seat the needle as well as pull it open....I would definitely check that.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Ok I'll have to post a pic of how the needle and float are installed so you guys might can tell me if it's wrong. The manual and the kit instructions aren't clear on it. Since the kit came with a different kind of needle than the one I took out, I wasn't sure how it went back in. That's tomorrow's project... today is putting stringers in. I'll post back with results.. thanks for all the help! I know I wouldn't figure all this out without the help..

 

[Gary H NC]

Re: Rebuilt carb, set float, still flooding?

I suspect the needle and seat also. The one in the kit is different? How?
It should be the same size and length.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

I'll post some pics of the different needle valves as soon as I get it apart. The best I can describe it without pics is the old needle valve had a shoulder and a "cap" on it where the float touches it. The new valve had a hole in the end of it where it looks like a pin would be inserted. It came with a little pin with a head on it that I figured would go into the hole in the valve, but the pin seems to be too small. And there was also a little "wire" springy clip in the bag with the valves, so I'm sure that has some use as well. I'll post pics.

 

[dn010]

Re: Rebuilt carb, set float, still flooding?

Make sure your float doesn't have a hole in it, and make sure it doesn't bind when you put the carb together. When you took the carb apart, was the float set too low? I have the same carb and had the same problem. New needle, seat, readjust the float and it is good now. But be careful and check your parts-just because its new doesn't mean it isn't defective!

 

[Silvertip]

Re: Rebuilt carb, set float, still flooding?

Some Rochester carbs had a check ball under the accelerator pump and if that was left out, the carb would overflow. It was very easy to lose that check ball upon disassembly. Are you checking float level with the unit inverted and checking float drop with the unit upright. If not, do it right. Before you put the thing together, invert the unit and blow into the fuel inlet. Without pressing on the float the air should be shut off. Turning the unit over and blowing in should allow air to flow. if it appears to be working ok, then the electric pump is providing too much pressure. Get the right pump on the engine.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Some Rochester carbs had a check ball under the accelerator pump

Silvertip, since this was the second time to rebuild the carb, I couldn't remember if it originally had this check ball or not. I do know that down in the bottom of the pump well, there seems to be a little ball stuck down in there, but it's not stuck in the center of the well, it's over to the side and appears to be about halfway in a hole. I tried to get it out, but since it was so stuck, I was thinking maybe it was meant to be that way. I wonder if this is the checkball and it's stuck? I'll take a pic of it if I can get a clear shot to show you what I'm talking about.

But if that is the check ball and it's stuck in there, wouldn't that cause less full rather than too much? There was 2 or 3 balls in the new kit and I only used one.

I did check the float level/drop with the carb upright and inverted as it explained in the manual. I know I got the measurements dead on, but I like how you suggested to check if it is sealing or not by blowing into the fuel inlet. I'll try that today when I get it apart.

dn, I'll look over the float one more time real good just to make sure I didn't miss any bad spots. I saw on one post where a guy floated it in some water to make sure it would still float good. Guess there would be no harm in trying that while I have it apart?

 

[LilRedNeckGirl]

Re: Rebuilt carb, set float, still flooding?

Rebuilding carbs isnt a science, it all comes down to using all the parts in the rebuild kit. My mechanic emphasised to me, the absolute need to replace the SEAT that the needle valve rests into, @ often overlooked. on units where its not replaceable, a good cleaning is in order.
also, check that the float is floating and not setting on the bottom because it has a hole in it.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

What confused me with the kits is they will come with many parts that aren't even used in some carbs because they are used for more than one model. Balls and springs and washer-type gaskets to be more specific.

I do agree on replacing the needle AND seat. It says on the packing that they come as a matched pair and should be replaced as so. Makes sense to me...

Heading out in just a minute to get it all apart. Will post with updates... thanks!

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Ok got it all apart again...

When holding it upside down so the float is closed, I blew into the fuel inlet. No matter how hard I blew, no air was coming out of the valve. Of course when I would lift the float a little to open the valve, the air would pass through then.
When holding the carb so the float was hanging open, I could blow air through it all day. Does this mean that the float is acting as it should? I checked the measurements again on the float level/drop and they are are still right on. Perhaps the pump I'm using is just too high pressure?

As far as the check ball goes, below is a picture of the little ball that is inside the pump well. Again, I tried to get it out with absolutely no luck. It doesn't budge. The carb kit sheet shows that if there is a ball that goes there, then there is also a retainer clip. I don't see a clip, unless that is the ring looking thing at the bottom just above the ball? It feels as though that piece is made into the carb and doesn't move.

The two different valves... one on the left is the type that I took out originally, on the right is the one that came in the kit.

-
Is this the checkball in question? If so, any tips as to how to get it out?

Thanks for keeping up with this thread.. I really appreciate the help!

 

[Don S]

Re: Rebuilt carb, set float, still flooding?

You should have a spring inside the needle valve that that end pin pushes on.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Wow, I didn't know that. That makes sense though. I didn't notice that little spring in my kit, so I'll have to go look back through it. It must have been in there somewhere. The needle, seat, and hopefully the spring came in a seperate little plastic bag so maybe the spring is still in the bag.

I wonder if it will be ok to just use the other needle that is in the picture? That's the kind that I originally took out of the carb when I first rebuilt it.

The reason I put another kit in it is the kit I originally had was the kit for the carb that had the smaller bore. Apparently they came in two different bore sizes. So some of my gaskets weren't the right size, including the pump. The one piece valve in the pic is from the first kit, and the valve with the spring is the one from the second kit.

If it is sealing when I blow air into the fuel inlet, does that mean it is working as it should?

 

[Don S]

Re: Rebuilt carb, set float, still flooding?

If it is sealing when I blow air into the fuel inlet, does that mean it is working as it should?

Hard to say, without knowing how much air or how you are blowing air into the carb who knows. I have seen some wild DIYer designed tests on here that were just plain useless.

 

[dccordell]

Re: Rebuilt carb, set float, still flooding?

Haha well that is true I suppose.. hey maybe I can judge the amount of air pressure I was blowing by my cheeks! I'll look for the spring and go from there.. thanks for the info Don