PDA

View Full Version : Carb flooding? @ idle - 4160, 351


Hoff1
07-20-2008, 04:48 PM
Hello everyone, been a while since I've been on Teamtalk. Apparently there were over 19000 new posts. New site looks great though.

Got a problem with my Holley 4160. 1990 MariStar, 351 ford. Was running good towards the end of last year. Power valve was blown, so I replaced that. Tore a fuel bowl gasket in the process. Fixed that, then tore the o-rings on the fuel transfer tube. Fixed those, but then the card started running terrible. It seems to be dumping way to much fuel at idle. Smokes, stumbles and won't idle. Will only stay running with a lot of throttle. Tried some carb cleaner and eventually got some more rpm's, but still won't idle.

I pulled the flame arrester off and there was a large amount of fuel dripping from the j-vent tube on the rear of the carb - attached a picture for reference. I'm sure a carb rebuild is in order, but wanted other people's opinion or ideas just in case anyone has seen this before. Thanks for all the help.

CantRepeat
07-20-2008, 05:13 PM
Hey,

If fuel is running out of that tube, the first thing I would check is the float level and the neddle and seat. Make sure they are closing off fuel once the fuel level gets high enough.

Hoff1
07-20-2008, 05:19 PM
Should no gas be coming out that tube?

I know very little about carbs. We'll to be more honest, i konw almost nothing about carbs.

CantRepeat
07-20-2008, 06:06 PM
Yeah, it's just a vent tube and no gas should be coming from it. If there is you either have a stuck neddle valve or a bad or miss ajusted float. I have the same carb on my 92 and did a rebuild last winter and boat runs a lot better.

Hoff1
07-20-2008, 06:45 PM
great, that's really helps.

i took it apart. moved the floats around a little and then put it back together. seems to work good now. just a little loud for the neigherbors. must have been a stuck float/valve or a gasket misaligned.

thanks for the help.

CantRepeat
07-20-2008, 07:04 PM
If the needle or the float have become sticky I would think about ordering a rebuild kit for it. They are sure to continue doing so.

Matt L.
07-24-2008, 10:03 PM
You need a rebuild. If it ran fine before then the floats aren't going to change on their own. The needle and seat will get sticky and cause exactly the symptoms you are describing.

Rebuild it and have some piece of mind for your next lake trip.

Here is a good article.

http://www.larrysengine.com/techarticles.asp

Later,

Matt

climbinggod
08-06-2008, 07:30 PM
I have a new 4160 and can't get it to idle in neutral when it is just been started. I try and get it off the trailer quick but it keeps stalling out. When it is warm she idles fine. Sometimes doesn't want to start when hot but put it in neutral and give a little gas and it's fine. I was thinking it was a carb idle issue. Does anyone have any ideas??

Cheers

Hoff1
08-06-2008, 07:42 PM
Well, my cold start idling issues from a couple years ago were more related to my distributor. When I ripped out the points and condenser and switched over to an electronic module, starting at the ramp became much more pleasurable. Best $100 I spent on the boat in the last 7 years. Very similar symptoms that you have. Ran fine once warmed up.

I don't remember what year that electronic became standard, but I thought it was 1992. How about the timing?

My recent idling issues were related to a clog or sticky needle valves and floats which was evident by the fuel coming out of the vent tube I showed above. Is your flame arrester clean?

climbinggod
08-06-2008, 11:21 PM
Mine does have the EI module. Haven't checked timing but runs fine as soon as warm, very smooth hole shot. My flame arrestor is clean.

knudsvig
08-07-2008, 10:18 AM
Hi, I noticed in the Hoff1 carburator picture that the choke was fully closed. If the picture was taken when the motor was cold, this would seem to be the correct position for the choke. If the motor was hot, I would have expected to see the choke open. I am suggesting that maybe your choke was stuck. When you removed the bowls, maybe you unstuck the choke.

knudsvig
08-07-2008, 10:31 AM
I noticed in your picture of the 4160 that the choke is on. If the engine was warm when the picture was taken, I would have expected the choke to be off. Maybe you have a sticky choke and when you took the bowls off to look at the floats, perhaps you unstuck the choke.