Carb adjustment after rebuild

[mrhoneydew]

I have a Zenith 68 that I recently rebuilt and I am trying to get this A4 started for the first time. It hasn't run since I have owned the boat and was neglected for some time. I put in a new Racor filter element and have a new in-line filter between electric fuel pump and carb. There is fuel getting to the carb... I pulled it and cracked the nut on the bowl and it was full of fuel. I also replaced the coil and re-gapped the plugs to .035. There is good spark. But the thing wouldn't fire. Then I sprayed some starting fluid in the spark arrestor and it fired and ran for a few seconds. So it seems I have an adjustment issue in the carb. Is there a rule of thumb for setting up a carb after rebuild? I am wondering if the idle speed and air mixture screws have a default I can start with. I need to hook up the choke cable, but I am able to pull it closed by hand when trying to start it so this isn't an issue.

[Al Schober]

First, welcome to the forum. All things A4 - and something other stuff too!
Rule of thumb for my idle air jet and also my adjustable main jet is 1 1/2 turns from closed. Give that a try too for the idle speed adjust & let us know how it works out. As a rule, choke is needed for a cold engine.
If it runs on starting fluid but not otherwise, the carb is suspect. Did you have any parts left over from your rebuild? What instructions did you follow for the rebuild? If you don't have the Moyer Maintenance & Overhaul Manual, recommend you make that a first purchase.

[mrhoneydew]

Thank you for the reply, Al. I got the rebuild kit from Moyer and I think I followed instructions that may have come with it? I did the rebuild a couple of months ago so my memory could be faulty. I will try the adjustments you recommend and report back. It has seemed like it was trying to fire a couple of times before I tried the starting fluid, so hopefully it's just going to take a bit more fiddling with it.

[Dave Neptune]

mrhoneydo, how old is the fuel? If it started on motor crack it should of kept trying unless the fuel is bad or the idle screw was closed(?).

Do you have a blue or yellow spark?

Dave Neptune

[JOHN COOKSON]

Are the spark plugs wet with fuel after a period of no start cranking?
Are you keeping the raw water intake valve on the through hull fitting closed when you have been no start cranking?

TRUE GRIT

[mrhoneydew]

Let's see...

* There were no extra parts left over after the carb rebuild.

* There was maybe a gallon or two of fuel in the tank, but it didn't smell shellacked and looked pretty clean. I added 5 gallons of super premium along with a can of Seafoam.

* The idle screw was open, though I just now adjusted both that and the fuel mixture screw down to closed and backed them off 1.5 turns.

* The spark is (now) blue. I put a new coil in it. Prior to that it wasn't even really firing on the starting fluid.

* Before the new coil the plugs had been wet with fuel. I haven't pulled them to look at them after it started to try to run on the starting fluid.

* The raw water through hull is (now) closed. Thanks for the reminder!

But... the *%#@! thing is still not firing without starting fluid. So... I goofed up something in the rebuild, I am guessing. Any common things to screw up? Could the float be stuck closed or something?

[mrhoneydew]

I was just talking to the guy in the slip next to mine and he came up with a good point... the fuel tank is metal and it has been sitting for well over a year and a half out of use. I could have a bunch of condensation in there. So... my next step is to disconnect the fuel line and put it into a spare tank of fresh fuel. If it fires on all new fresh gas then it's the fuel in the tank.

[Dave Neptune]

mrhoneydo, trying fresh fuel is the next thing to try. Did you adjust the points at all?
If you can pull the plug on the bottom of the carb and hold something under it to catch the fuel. Put the fuel in a glass or jar and let it settle for a bit. Then slosh it around and if you see 2 liquids rolling around with each other and not mixing bingo water in the fuel. The fuel also has a finite life before it begins to separate and this can look brownish in color.
Stay away from additives for now and regular fuel is more than adequate for the A-4. In fact it will make more power with regular than premium with the A-4's low compression.
One step at a time and it will be an easy chore for such a simple motor. We can deal with the coil replacement "reasons" later.

Dave Neptune

[JOHN COOKSON]

. It hasn't run since I have owned the boat and was neglected for some time.

Fuel, spark, compression all delivered to the cylinder. Properly functioning choke and correct timing.

It's very possible since the engine "hasn't run since you've owned the boat and has been neglected for some time" you have one or more stuck valves.
We know you have spark. Once you get the fuel side squared away if it's still no go it's time for a compression check.

TRUE GRIT

[Mo]

Fuel, spark, compression all delivered to the cylinder. Properly functioning choke and correct timing.

It's very possible since the engine "hasn't run since you've owned the boat and has been neglected for some time" you have one or more stuck valves.
We know you have spark. Once you get the fuel side squared away if it's still no go it's time for a compression check.

TRUE GRIT

Concur...compression check necessary. Starting fluid is more volatile than gasoline so it doesn't surprise me that it started for a second or two. Valves stuck sounds likely. Compression check will let you know...use a gauge.

[BadaBing]

I feel inspired to remind honeydew that. " you are working in as confined space with highly flammable liquids and fumes which are heavier then air, meaning they fill the bilge like water AND your messaging with a very active ignition source.
Keep the blower and or all hatches open! A very small amount of gasoline in rapidly evaporating mixed with a very small spark makes a big mess.
The suggestion to check the fuel quality is A1. As a matter of fact it might be considered prudent, considering how little there is in the tank, to just suck it all.out of the tank. I do so With the same hand powered, plastic constructed vaccine po I use to change my oil. Your boat fuel pickup should be a few inches off the bottom of the tank. This is to allow scrap and unfortunately water as well,to sink to the bottom of the tank. The addition of 5 gal of fresh gas may have stirred up a mess that is now in your fuel lines and filters.

Follow the above directions to drain the bowl and look at the fuel you collect, please carefully collect it as described.
I'm guessing your going to find snot, Brown glass looking the color of strong tea, and flakes of grit. If so the challange will be to carefully purge the tank, lines, filter, fuel pump and assessment bowl, if you have a mechanical pump, of the old gas and its critters. Than 're- clean the carb and its jets and ports, prime it up to where you know fuel is making its way into the float bowl. Theory vent the bilge and start her up.

Is there any reason you having done a compression test yet?

[HOTFLASH]

Got Type A2 Hoses?

Mrhoneydo,
Are your fuel hoses type A2 (or type A 1-15) for the alcohol in the gas? Old hoses may not be. The alcohol makes ones that are not shed little bits of hose material and make the tiny passages in your carb unhappy.
Mary
HotFlash
T27 Yawl

[Dave Neptune]

Mary, great post. That should be sort of a standard response for fuel issues on recently bought boats and those of little TLC!

Hopefully I will remember it, I was raised in the 60's.

Dave Neptune

[HOTFLASH]

Learned this (again) from a "disabled" patient

Dave Neptune,

I am a psychologist (and no engine geek). I do what I do on my A4 from what I learned in 5th grade science class and mostly from this forum. Kinda like paint by numbers. Smart numbers created by smart Afourians.

Had a patient, an accomplished mechanical engineer, who, because of some brain damage from a car accident, could no longer do that, and so he took on small mechanical fix-it jobs. One was a rebuild of a fuel system of a little used old motorcycle. Turned out the problem was the old pre-ethanol hoses sending tiny black specks to the carb. I had remembered seeing those specks in my A4 mechanical pump during rebuild, and also hose upgrade, and suggested that to him. Turned out that was the problem in his motorcycle.

They did not teach me that in my PhD (Piled higher and Deeper) degree. All of you did. And my patient thanks you .

Mary
HotFlash
'74 T27 Yawl #570

[mrhoneydew]

Hi all. Thank you all for the information and insights. Turns out the water in the fuel tank was the problem. I drained the carb, pulled the fuel line at the Racor filter and drained the line, and then placed it in a jerry can of fresh gas and it started! Ran for about 20 seconds and died. I have some things to dial in, but I am well on my way, I think. I pumped all of the fuel out of the tank and will re-fill it and have another go (after I pull the Racor element and clean it).