Quick Holley 4160 Question...

[JustinB]

Is there something in the carburetor that would shut down the fuel delivery completely? A float or something that could become stuck? Is there something that could be jostled (say when you hit a wake) and close off the fuel supply?

[NigelC]

RE: Quick Holley 4160 Question...

To answer your question, the float could stick either open or closed or somewhere in between. I guess you are referring to the primary side??
Does the boat start OK?? when does the fault present itself?? Any other info you could provide would help to diagnose.

[JustinB]

RE: Quick Holley 4160 Question...

Thanks for the quick response.

I've had difficulty starting the boat, and noticed that no fuel was flowing into the carb at all...it starts ok if you pour gas directly into the carb, but dies as soon as it runs out. It miraculously started working the other day, but died after about 2-3 minutes of driving and wouldn't restart - looking at the carb, once again no fuel was flowing.

So Friday I connected a new fuel line directly to the fuel pump and ran the hose into a fuel can (bypassing the filter, anti-siphon valve, and the pickup tube)...it still wasn't getting fuel. I disconnected the fuel line that goes from the pump to the carb (pump side) and a bit of gas drained out of that tube...I turned the boat over to see if the pump would spit some gas out...which it did. So I connected everything back together and on a whim turned it over - it started right up. I let it run for about 30 minutes at the dock and it would turn off and fire right up without issue. I didn't untie the boat from the dock and go for a ride because there wasn't anyone on the lake and I didn't have a paddle in the boat (I don't believe the issue is resolved).

So I was guessing that maybe there is a float or something in the carb that got stuck and prevented fuel from flowing, when I let the gas drain from the tube running up to the carb it relieved the pressure and let fuel flow properly again? I'm worried that if that is the case, once I'm under load and hit a wake that it could jostle it again and prevent the flow of fuel? That is the only thing I can come up with as that is when the fuel supply seems to shut off. I don't know that much about carbs, so I'm taking a guess that there is something in the carb that would function like that?

[Toster]

RE: Quick Holley 4160 Question...

It definitely could be a float valve. More than likely it would be on the primary side. (The side with the choke butterfly on it.) It is usually toward the front of the boat. You could try some fuel cleaner stuff in the tank, but I have not had too much success with those products. Maybe the stuff made by Seafoam. Otherwise you might need to take the carb off and take it to a shop to have them rebuild it. You will have to set the idle and needle valves once it is back on the boat though. If you don’t feel comfortable doing that, make sure whoever rebuilds it comes/takes it on the lake for a test drive/setup. I have been told the 4160 are really easy to rebuild but have never done one myself. The diaphragm on mine was leaking, so I bought a complete carb kit from Speedway Motors for about $30 replaced the primary gasket, and the leaking diaphragm.

[NigelC]

RE: Quick Holley 4160 Question...

There are four screws that hold the primary float bowl in place. Remove the fuel line, remove the four screw and pull the float chamber away from the main carb housing. This will also disconnect the fuel line to the secondary float bowl.
You will be able to see inside the primary bowl and check the float. Also check the fuel valve for contamination. Before any further disassembly, I would measure the position of the float against the housing but I do not have the measurement for you to check the setting. Hopefully someone else may chip in.
Reassembly is a reverse of above. I would have a new gasket at the ready as you will probably destroy the one that is already fitted.
I would actually get hold of a refurb kit for the 4160 that includes new gaskets etc and an instruction sheet. They shouldn't be too expensive.

Hope this helps

[NigelC]

RE: Quick Holley 4160 Question...

Additionally, have you checked the filter that is located where the fuel line attaches to the primary side?? This is behind the big brass nut.

[AirTool]

RE: Quick Holley 4160 Question...

The 4160 carb is easy to rebuild. Note when you put the gaskets on between the plates that you TRIPLE CHECK the orientation. If you get a gasket upside down, or backwards, or upside down and backwards, ....you are toast.

Your local Mercruiser dealer, Adademy, or Bass Pro should have some Quicksilver carb cleaner. It comes out like shaving cream and doesn't drain away fast. With the carb on the boat, you can stick the spray tube into every orifice you can get to...the jets, the fuel inlet, the vent at the air horn, etc. Foam the **** out of it and let it sit overnight. If you have trouble starting it, pump the trottle full strokes as fast as you can while someone else cranks. This will pump fuel through the accellerator pump straight into the intake. If this doesn't work, time for a rebuild. Check the weight of your floats to be sure each is not saturated w/fuel or just buy new ones even though they are expensive.

[nms1991]

RE: Quick Holley 4160 Question...

It sounds like you may be having a problem with the fuel delivery to the carb and not in the carb. Check to see if your fuel filter is loose or has a hole in the case. Also it is highly un like ly the float becomes stuck shut in a holley carb unless it is varnished closed or it corrodes shut from water in the fuel. I really do not think your problem is in your carb and it is very hard to see fuel flow thru the idle system on the carb, so check and see if your fuel bowls have fuel in them pump the throttle to see if the accelerator pump is shooting fuel into the carb.

[Andrew]

RE: Quick Holley 4160 Question...

The floats can crack and form a leak, fill with fuel and stay in the down position ( I don't remember whether that is open or closed though) However, I honestly do not believe that is your problem....

[skijones]

RE: Quick Holley 4160 Question...

Napa part number for the rebuild kit is 335-3457. Couple cans of carb cleaner and you should be good to go.
Holly prints a book on the 4160 that is very instructive, less than $10, I think.
Takes all the mystery out of carbs.

[JustinB]

RE: Quick Holley 4160 Question...

Thanks all for the suggestions, I appreciate it.

The carb was rebuilt prior to my purchase at the local marine dealer. I pinged the guy there yesterday and this was his response...

"That carburetor was beat, I know you can get new marine carbs online for 3-5 hundred and that might be an avenue for you. Even though we rebuilt that one I think maybe the internals were just beat too bad and it might be creating some of the issues. I would check for debris in the mesh screen first because when she first brought the boat in that mesh screen where the fuel supply enters the carb was jam packed with this white stuff (maybe old fuel filter parts) we flushed it out but maybe there is some collecting there again, but you'll probably be better off buying a new carb."

So his advice appears to be that I purchase a new carb...if I order one, is there much I'll need to do other than bolt it in place and reconnect the throttle linkage? Sorry for the silly question, I'm not afraid of tackling any job and am very mechanical...I just don't have any experience/knowledge when it comes to carbs.

[Mikeski]

RE: Quick Holley 4160 Question...

http://cgi.ebay.com/ebaymotors/Holle...Q5fAccessories

Jet it to match your existing carb before installation.

[JustinB]

RE: Quick Holley 4160 Question...

Thanks...what is the main difference between the "universal" one noted above and the Ford specific model, other than the Ford specific is $70 more?

[Andrew]

RE: Quick Holley 4160 Question...

How on Earth does a carb become "beat"?

[NigelC]

RE: Quick Holley 4160 Question...

I agree with Andrew.
If you do decide to replace, be aware there are different models of 4160. You can identify the exact model by finding the four digit engineering 'LIST' number which is usually printed in the vertical face of one of the primary venturi's (eg. 6979). This will define the build and jetting.
I would be inclined to do my own refurb before replacement as recommended in posts above particularly that you have been informed there has been previous fuel contamination.