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View Full Version : Need carb help - Just rebuilt 4010, having issues


James O'Keefe
07-30-2006, 07:50 PM
It will start if I open the throttle all the way, but runs rough, and won't run unless I keep it at 2000 rpm or above. It's just dumping fuel into the secondaries...

Any quick suggestions?

I don't know that much about carbs and may have bit off more than I can chew with this project...

James O'Keefe
07-30-2006, 10:26 PM
I think the secondary float is out of adjustment, and it's allowing too much fuel. The needle and seat was screwed all the way in before the rebuild, so I figured that would be a good place to start. However, I did just notice that one of the original screws was longer than the other (not sure which at this point). I checked the new ones that I installed from the kit and they are both the same length (same as the shorter original). I think I need the longer one for proper adjustment.

Any thoughts/suggestions? Please help???

east tx skier
07-31-2006, 10:41 AM
BUMP for you. You don't want to hear my suggestion about the 4010. :)

James O'Keefe
07-31-2006, 04:57 PM
Thanks for the bump. I've have read almost every thread on the 4010, so I know what I'm up against, just don't have the extra money for a new carb right now. Did the rebuild to get rid of the hesitation, but not really expecting idle issues to be alleviated...

Does anyone have any suggestions?

Hoosier Bob
07-31-2006, 05:15 PM
Run to your autoparts store (Pep Boys is where I got mine) and get the Holley Carburetor Manual. Very helpful for me. Regarding the 4010 it says your secondaries should be set as follows. You should see a sight hole on the side of the float bowl. Flat head cap screw. They are on the fuel line side I believe. It says to loosen the lock nut on the set screw (on top of bowls with lock nut) and adjust so fuel trickles over the threads of the site hole. If you remove the site hole and fuel is running out obviously they are too high. Hope this helps.Thanks for the bump. I've have read almost every thread on the 4010, so I know what I'm up against, just don't have the extra money for a new carb right now. Did the rebuild to get rid of the hesitation, but not really expecting idle issues to be alleviated...

Does anyone have any suggestions?

James O'Keefe
07-31-2006, 07:38 PM
Update:

I switched out the new needle and seat screws with the old. It made a huge difference, it actually was idling @ 600 rpm, but rough. It's also rough when I rev it.

One interesting thing is that once it was running, I turned the air/fuel mixture screws all the way in and then two turns out. It made no difference in the idle at all??? I have done this before, as described on this site and the skidim tech section, and got the hissing/almost stalling and then backed them out a little. Don't know why it doesn't do anything now.

It also seems like there is more of a hiss than before, pretty much at all speeds.

Getting closer but still looking for input from the experts...

Hoosier Bob
07-31-2006, 08:54 PM
NO SIGHT SCREW ON MARINE 4010's! Thanks James, just checked and mine is void of the sight screws at well. Best way I know of now is running and viewing down the horn while you adjust slowly. :o Run to your autoparts store (Pep Boys is where I got mine) and get the Holley Carburetor Manual. Very helpful for me. Regarding the 4010 it says your secondaries should be set as follows. You should see a sight hole on the side of the float bowl. Flat head cap screw. They are on the fuel line side I believe. It says to loosen the lock nut on the set screw (on top of bowls with lock nut) and adjust so fuel trickles over the threads of the site hole. If you remove the site hole and fuel is running out obviously they are too high. Hope this helps.

Hoosier Bob
07-31-2006, 08:55 PM
NO SIGHT SCREW ON MARINE 4010's! Thanks James, just checked and mine is void of the sight screws as well. Best way I know of now is running and viewing down the horn while you adjust slowly. :o Run to your autoparts store (Pep Boys is where I got mine) and get the Holley Carburetor Manual. Very helpful for me. Regarding the 4010 it says your secondaries should be set as follows. You should see a sight hole on the side of the float bowl. Flat head cap screw. They are on the fuel line side I believe. It says to loosen the lock nut on the set screw (on top of bowls with lock nut) and adjust so fuel trickles over the threads of the site hole. If you remove the site hole and fuel is running out obviously they are too high. Hope this helps.

James O'Keefe
07-31-2006, 09:55 PM
It's running better now. It's idling consistent and smooth @ 600 rpm and revs pretty good. It seems a little starved for fuel when I first start it up though.

I also may need to adjust the choke.

Unrelated, I think my starter might be going too...

I'll be doing a lake test tomorrow to see how it runs.

I'm still confused on why the air/fuel mixture screws do nothing from screwed all the way in to 3 turns out??? They worked properly before the rebuild?? Can anyone help there?

scott88prostar
08-24-2006, 05:05 PM
Cant you replace the screws on the side with sight screws( auto parts store)?....less than 10 bucks.

Hunterb
08-24-2006, 06:17 PM
I'm not sure but I think if you can screw your mixture screws in all the way and the motor doesn't stall it may mean thay you have your secondary throttle plate open too much. I had that problem with a 4160 carb anyway. Once I closed the secondary throttle plate at idle then the mixture screws worked properly. Having that throttle plate open is like having a big vacuum leak. That may or may not be the case with the 4010.

Hope that helps. Good luck with it.

Bruce

wesgardner
08-25-2006, 10:09 AM
Once upon a time I rebuilt my 4150 and prior to the rebuild I did a bunch of research and bought some manuals...I think and I can't really recall with certainty which one, it was the red Holley book that went thru the whole litany of adjusting the mixture screws (initially should be set at 1 1/2 turns out) and some issues that more or less described what is being exzperienced here - no affect from these screws...so the info is out there somewhere (or al least it is for the 4150) the initial set up for the floats was to adjust them so they're level with the carb turned upside down (once again, this is 4150 data but it seems pretty universal...)one of my problems is someone had put the jets back in weird with an unmatched set it both primes and seconds...here's a link to jetting if you know your "list" number...

http://www.mortec.com/carbs.htm

tdaines@hotmail.com
09-10-2006, 10:10 AM
Hey man - just a quick note...I'm a lover of old MC boats, and thus have had this problem many, many times. The thing about carbs, especially marine carbs is that they were never meant to last 15+ years...

I've learned the hard way that you can fight with secondaries, you can rebuild, you can have crappy ski days for a long, long time. But the only way to get your boat running like a fuel injected boat is to get a new carb...

If you priced out a new 4010 at the MC dealer and got the same price I did - $730...you're in luck, I can save you $220 on that price.

Go down to your local NAPA store, and have them order you a new Marine Holley 4010, they have them right in their carb catalogs, and they're $509. It's a 10 minute job to change it out, and you won't regret it for one second - the first time you fire that thing up it will run like a new boat!

Good luck

east tx skier
09-11-2006, 11:36 AM
Are marine 4010s still available from MC? Indmar was most recently using 4150 dual feeds on their carb'd engines for other manufacturers.

Hunterb
09-11-2006, 01:04 PM
I don't know for sure on that carb, but on a 4160 if the mixture screws are not having any effect it means something on the carb is not set up properly. When mine did that it was bacause I had the secondary throttle plate open slightly at idle. Once I closed that plate the mixture screws became effective. If you can screw the mixture screws all the way in and the motor still runs then it is getting air and fuel from somewhere that it shouldn't be at that point. I'm not very familiar with the 4010 carb but the principle should be the same as the 4160.

Good luck. There are a couple of very knowledgable carb people on this board who should be able to help you.

Bruce