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hz900
08-03-2009, 02:16 PM
'92 Prostar 205

First off I have the hated 4010 carb, but a new one is not in the budget right now so I have to deal with what I have, so if you are going to say just buy a 4160, that won't help me right now, I already know that solution.

I rebuilt the carb myself ~4 years ago with a Holley kit. I set it and it ran good for several years. This year I noticed it has been using an unusual amount of gas over what I remember it used to use, so I decided to readjust the idle/air mix screws to make sure they were still in line. In neutral at ~2K rpms, I can screw the idle screw in all the way on the left side(facing forward) of the carb and nothing happens. If I remeber right you are supposed to screw in until it starts to kill the engine and then back off 1/2 turn. I did not try the right side because I figured it pointless if the left side couldn't be set.

I remember reading about other people having the same problem and it is usually something simple to fix. Can someone give me some ideas on where to start.

lilsumo
08-04-2009, 02:17 PM
First off, 2000 RPMS is not idle, check it about 600 RPMS and yes it should kill the engine. From what you have told me, It's a blown power valve. Take it off and check it.

You have all the symptoms of a bad power valve. Has it backfired anytime lately? Check the plugs for being black.

TMCNo1
08-04-2009, 02:44 PM
First off, 2000 RPMS is not idle, check it about 600 RPMS and yes it should kill the engine. From what you have told me, It's a blown power valve. Take it off and check it.

You have all the symptoms of a bad power valve. Has it backfired anytime lately? Check the plugs for being black.

Correct, 900 rpm in neutral at idle and 600 give or take at idle in gear.

hz900
08-04-2009, 02:55 PM
I also emailed Vince at Skidim and he said the same thing, I will do that, for some reason I thought I remembe having to have it at higher rpm to do that. Also he asked if I could see gas dripping into the carb. I can, and I even see it dripping a bit after I shut the engine off. Its not pouring by any means, but there is definitely a slight drip. Vince suggested a rebuild to fix this problem, which is out of the question, I'll figure out a way to buy a new carb before I do that again or I'll deal with the crappy gas mileage for another 5 weeks or so. Any quick fixes for this that will get me through the rest of the season here, mid Sept.

lilsumo
08-04-2009, 02:58 PM
A new power valve, cost about 8 bucks, if you know the correct one, Advanced auto parts can probably even get it for you.

thatsmrmastercraft
08-05-2009, 02:07 AM
The simple old way to check if your power valve is blown is to hold the big end and try to turn the small end. You should not be able to turn one end without the other end turning.

If you replace your power valve, make sure you get the same valve. There is a number on it which corresponds with when it opens. Pretty simple and cheap repair - as far as repairs go. Good luck.

mayo93prostar
08-05-2009, 07:54 AM
the power valve may be one problem but the dripping gas after shut down may be due to float adjustment. I had to adjust the float on the front bowl of mine to keep it from dripping after shut down. the screw/nut on top of the bowl is used to adjust the float.

hz900
08-05-2009, 12:05 PM
the power valve may be one problem but the dripping gas after shut down may be due to float adjustment. I had to adjust the float on the front bowl of mine to keep it from dripping after shut down. the screw/nut on top of the bowl is used to adjust the float.

I changed the power valve out yesterday evening and that changed nothing. So I called a friend's dad that is into hot rods and he said it sounded to him like the float was out of adjustment. Even though it was not flowing out of the J tubes, it could still be a bit to high, and I should adjust the float in 1/2 turn increments. I am going to try that this evening. Thanks for all the suggestions.

TMCNo1
08-05-2009, 12:22 PM
I changed the power valve out yesterday evening and that changed nothing. So I called a friend's dad that is into hot rods and he said it sounded to him like the float was out of adjustment. Even though it was not flowing out of the J tubes, it could still be a bit to high, and I should adjust the float in 1/2 turn increments. I am going to try that this evening. Thanks for all the suggestions.


You should have bowl sight access screw/plug (gold screw plug on side of bowl in picture) on the side starboard side of each bowl. While the engine is running at idle, remove the access hole screw/plug from the front bowl and raise or lower the float using a screwdriver on the screw/nut on top of the bowl after you have backed off the jamb nut till the fuel just appears to just start running out of the sight hole, then tighten down the nut under the float adjustment screw on top of the bowl, repeat on the rear bowl. After your finished, adjust the idle air mixture screws on both sides of the front bowl. Idle rpm may change some then, so if need be adjust the idle speed with the spring screw on the port side near the linkage.
50213

hz900
08-05-2009, 12:34 PM
You should have bowl sight access screw/plug (gold screw plug on side of bowl in picture) on the side starboard side of each bowl. While the engine is running at idle, remove the access hole screw/plug from the front bowl and raise or lower the float using a screwdriver on the screw/nut on top of the bowl after you have backed off the jamb nut till the fuel just appears to just start running out of the sight hole, then tighten down the nut under the float adjustment screw on top of the bowl, repeat on the rear bowl. After your finished, adjust the idle air mixture screws on both sides of the front bowl. Idle rpm may change some then, so if need be adjust the idle speed with the spring screw on the port side near the linkage.
50213


No sight holes on the 4010 if I am not mistaken.

TMCNo1
08-05-2009, 12:42 PM
No sight holes on the 4010 if I am not mistaken.

Is it a single line or dual line fuel feed?

hz900
08-05-2009, 01:16 PM
Is it a single line or dual line fuel feed?

Dual Feed .

Dan K
08-05-2009, 01:34 PM
While the engine is running at idle, remove the access hole screw/plug from the front bowl and raise or lower the float using a screwdriver on the screw/nut on top of the bowl after you have backed off the jamb nut till the fuel just appears to just start running out of the sight hole, then tighten down the nut under the float adjustment screw on top of the bowl, repeat on the rear bowl.

You should not run the engine when adjusting float levels, this is a fire hazard. The manual says run engine, shutdown, inspect, make adjustment and close before running engine again.

hz900
08-06-2009, 12:41 PM
Ok so I worked on this last night. I was only adjusting the front float, but I already had it adjusted almost all the way down. I adjusted it as far as it would go and it is still doing it, and now it is not just dripping when I turn it off, it is a steady pour/run off for 10 seconds or so.

Is it possible that the floats are bad or something in the bowls? or could this possibly be related to the jets somehow?

WilliM1940
08-06-2009, 01:22 PM
I had the same problem this year, and replaced the floats. There are numerous mentions in other forums about nitrophyl floats being attacked by the ethanol in gas and losing their bouyancy, or just slowly sinking over time. It could be your inlet valve not seating properly. I rebuilt my carb just two years ago, but last year it was going south. The inlet valve point from this rebuild was colored white versus the previous rebuild when there was no color change. Long story short, new rebuild new floats, smooth as a baby's a$$. With the ethanol, waiting on next year.

hz900
08-06-2009, 01:50 PM
I had the same problem this year, and replaced the floats. There are numerous mentions in other forums about nitrophyl floats being attacked by the ethanol in gas and losing their bouyancy, or just slowly sinking over time. It could be your inlet valve not seating properly. I rebuilt my carb just two years ago, but last year it was going south. The inlet valve point from this rebuild was colored white versus the previous rebuild when there was no color change. Long story short, new rebuild new floats, smooth as a baby's a$$. With the ethanol, waiting on next year.

I know O'Reilly has a bunch of Holley parts that they keep in stock, do the floats have to be the exact same, or will most floats interchange? I really don't think it needs a complete rebuild, I just need to find that one part that is not working properly. I'm trying to get this atleast somewhat worked out by Friday night, I've got plans that involve the boat, and the plans are kinda shot without it.

WilliM1940
08-07-2009, 10:50 AM
For a marine carb they have to be the same, got mine from Skidim, there is an adjustment tab not present on externally adjusted floats, and they only come in nitrophyl. I would have preferred brass with the ethanol fuel. I wasted a week trying to fix the single part problem versus just doing the whole rebuild in a few hours. In any event, I could not adjust my floats to prevent dripping onto the throttle plate and idle mixture screw adjustment kept wandering. The inside of the carb was clean as a whistle. Money vs unproductive time chasing a frustrating problem.

thatsmrmastercraft
08-07-2009, 11:24 AM
I believe they are only available in nitrophyl because they don't have the complete sinking problem that a brass float can have. They sure do have the slow-sink problem that can drive a guy crazy.

I have a lot of experience with Holley carbs so throwing in a carb kit every year or two for $25 is a no brainer.

hz900
08-10-2009, 12:08 PM
Thanks for all the help you guys gave me. I think I've got it worked out good enough to last the season and wait until winter to buy another carb, 4160. It turned out to be either the float was set to low, or a combination of that with the needle and seats. I had the adjustment almost all the way down to adjust the float and still nothing. I pulled the floats and found the tabs were almost flat, so I bent the tabs a little so I could get a little more adjustment and now she runs without any drip at all while in gear at any speed, and with an extremely slight drip at idle in the primaries, but so slight I can live with it.

Only problem I have now is the hesitation/wanting to die when the boat is put into gear, which I know is common of the 4010, but I never really had that before, but I can live with it for now.

Dan K
08-10-2009, 12:19 PM
Glad your getting to use the boat at least for the balance of the season. The season is always too short no matter where your at.