Startup (and other) issue

[sdemore]

Another question guys. I picked up the project boat with the engine in pieces last winter. I rebuilt it all over winter and put it back in the project boat in the spring. Boat went into the water 6 or 8 weeks ago. Until recently, the engine startup procedure was choke closed, fresh water pump on, ignition switch on, tap the starter button for a fraction of a second and she fired right up (then I open the seawater through hull). Three weeks ago, I had to crank it for a good 30 seconds to get it started. Two weeks ago, I cranked a few 15 - 30 second shots with no luck, gave it a shot of starting fluid, and it started right up. This weekend (Saturday), several 15 - 30 second bursts and multiple shots of starting fluid and and it finally started when I was about to give up. At idle, it stalled several times, which has never happened before.

Sunday I set the carburetor idle mixture back to the starting point, one turn out from seated. It had been at about 1 3/4 turn out (replaced the oil pressure sending unit nipple that I broke off in the process). I checked the timing and is was about 10 degrees before TDC. Dwell was down around 20 degrees. Dialed the timing and dwell back to TDC and 31 degrees dwell.

Still had difficulty starting until a few hours later. Since then, every time I start it, it is a quick press of the starter button (less than a second) and it fires right up.

I have never had a carbureted engine, with spark, fuel, and starting fluid, fail to cough, sputter, or make any indication of fire in the cylinder. Somebody told me that when I pulled out of the slip on Saturday, it sounded like the engine was "loading up" (flooding). I didn't know an engine sounded different when the carb was flooding, so am curious about that.

So my question is, could the idle screw being out 1 3/4 turns cause the engine to flood? Everything seems ok again now, but I have a little uneasiness about trusting it right now. Any suggestions?

[JOHN COOKSON]

Check the choke adjustment to be sure it is all the way open and all the way closed when you think it is. Also be sure there is no slipping in the choke cable. The outer cover of choke cable may be loose and slipping at times. Sometimes the outer cover comes loose in the hold down at the carburetor end.

TRUE GRIT

[edwardc]

It could just be the colder weather. In warmer times, Mine always starts on the second or third try when not warmed up. But yesterday, it took about six extended tries to get it to start. This is typical behavior (for my A4) at this time of year.

[roadnsky]

When was the last time you rebuilt and/or cleaned the carb?
It might be trying to tell you something...

[Dave Neptune]

The idle screw is for air, you are richer at 1 turn than at 1 3/4 turn off the seat.

An updraft carb on any engine including the A-4 should be a bit of a "cranker" as far as starting, as the fuel needs to drawn "UP & OVER" to get to the cylinders!! If it is easy to start as you state just touching the starter then you have to much fuel and the engine loading up as your dock mate stated would be the norm.

Dave Neptune

[edwardc]

Thats why I love my Fuel:Air ratio gauge. Combined with an adjustable main jet, it lets me dial-in the mixture just right and there's no question.

This does, of course, mean its a bit hard to start cold, as previously mentioned, but I usually keep it just a hair on the rich side of the perfect mix, to make it a little bit easier to start when cold.

[sdemore]

When was the last time you rebuilt and/or cleaned the carb?
It might be trying to tell you something...

In the boxes of parts, I had 2 old, cruddy carburetors. I sent one off to a place in New Jersey to be cleaned, stripped, anodized, and rebuilt. I called to check on status about once a month and heard it was all ready and would be shipped out to me tomorrow. After 6 or 7 months, I just gave up and called it a loss. I cleaned the other one up and used it to start the motor the first time. About that time, somebody was selling a "Moyer rebuilt" carb that he had been carrying as a spare for 3 years, having never installed it. I managed to win the bidding at $100. It showed up in the original packing, having never been opened, so I installed it.

I haven't rebuilt the other one per se, but took it all apart, cleaned everything and blew out all of the passages, so it works pretty well now as a spare.

[sdemore]

Starting Problem - follow up

Still having problems with hard starting. The engine is now running great once it starts, but is a nightmare to get started. This morning, I tried starting it before going out for a sail (45 degrees). Cranked it quite a bit before it finally started. Let the engine warm up and restarted it (easily) several times, just to be sure. Motored out into the Chesapeake and sailed for 6 or 7 hours (my first time sailing - woo hoo!). Coming back into the marina, the engine wouldn't start. I've already made sure the timing and carb adjustments are good, have spark and compression, so felt sure it was fuel. When I manually pump the mechanical fuel pump, the wire moves freely, but it isn't engaging the plunger at all (this is after cranking and cranking, so it may just be pressure). I thought it might be a flooding issue, so I moved the throttle to full open and tried again. It fired right up and coughed a bit (backfired through the carburetor) until it cleared out the excess fuel.

If I disconnect the fuel line at the engine, I get fuel running out of the line, so the tank is higher and gravity is flowing toward the engine. I'm trying to figure out what would cause the engine to flood while not running, but wouldn't cause any leaking fuel in the engine compartment. If the float was out of adjustment, I would think I would have leaking issues.

Any thoughts or suggestions?

Steve

[roadnsky]

Are you using your choke when cold starting?
Are you CERTAIN that the choke is engaged (closed) all the way?
Note that the only way to be certain is to take off the Flame Arrestor and look.

[edwardc]

Steve,

I've got to say that, at 45 degrees, this sounds pretty normal to me.

The updraft design of the A4's carb means that it will naturally be a little hard to start cold, even when properly tuned and choked. Cold weather makes it that much worse. I have an adjustable main jet, and an air: fuel ratio gauge, so I know that mine is spot-on at 14.7:1. In the summer, when its warm, it always takes 2-3 tries to start cold with a full choke. When its this cold, it can take a dozen or more tries.

What I've found is that, in the cold weather, the gas doesn't vaporize as readily, resulting in some gas droplets settling in the bottom of the carb throat (that's what the scavenge tube is for). So what I do after every attempt is to turn the ignition back off and wait 15-30 seconds before trying again. This seems to give the liquid gas a chance to evaporate more, resulting in a pop or two on the next attempt. Eventually this process gets it to start, without accumulating a lot of excess gas in the bottom of the carb.

Of course, all of the above is done with the water valve closed.

And if you're really desperate to get it started, a shot of the dreaded "motor crack" (aka ether or starting fluid) should make it start right up, but its only for occasional emergency use.

BTW, congrats on getting her together and out on the water! We winterized ours a few weeks ago, and just took the sails off this past Friday. After spending last winter in the Bahamas, 45 is WAY too cold for me!

[JOHN COOKSON]

I thought it might be a flooding issue, so I moved the throttle to full open and tried again. It fired right up and coughed a bit (backfired through the carburetor) until it cleared out the excess fuel.
Any thoughts or suggestions?
Steve

Just a couple of comments.
It is hard to impossible to flood an engine with an updraft carburetor by the "usual method". In a V8 engine excess fuel will run down into the engine. In the case of an updraft carburetor the excess fuel will pool at the bottom of the carburetor. In the A4 this pooled fuel is removed by the scavenge tube.
The only way I know for an engine to backfire through the carburetor is for the spark plug to fire when a intake valve is open.
Have you serviced the advance recently? It is a bit of a long shot but sticky advance could be a contributing factor.

TRUE GRIT

[sdemore]

I thought it would be difficult to flood this engine as well, but they symptoms certainly appear to be pointed in that direction. If I catch it in the first few attempts, a very quick shot of starting fluid (motor crack) will fire it right up. After 8 or 10 attempts, starting fluid doesn't make a difference. My problem is that I don't like using it, so I normally don't try until it is too late.

I haven't tried the waiting 15 seconds between tries, but will do that. I am using my choke and it was fully closing before. When the engine does start, I have to open the choke pretty quickly to get the engine to idle/run properly. It runs pretty slowly and rough with the choke closed.

I just tried the full open throttle (old time flooded engine fix) this one time. I'll give it another shot next time I make it home before dark to see if it really is flooding.

edwardc, I was hoping to run into you before you pulled yours out, I believe we are neighbors. I'm at White Rocks and I thought you had said you were at Oak Harbor. Perhaps next summer!

Steve

[Bratina]

I haven't seen it mentioned, but are you sure you're using clean, fresh gas? In my first year of engine ownership I had similar symptoms, which I chased for a long time, until finally I poured gas out of the fuel-water separator and found a large amount of water.

[sdemore]

I haven't checked that yet. I started with a clean, dry fuel tank and poured in ~7 gallons from my gas can in September. The engine probably has 1 1/2 - 2 hours on it now since rebuild/install.

One concern that did pop up is, I used my normal lawnmower gas, so it is just regular grade. I read somewhere that the A4 needs higher octane, but I would think that would cause a knock, not a starting issue.

I'll check the fuel-water separator this weekend and see what it looks like.

[sastanley]

hold the phone!

Steve, exactly the opposite. Higher octane fuel burns slower, and is designed for high compression engines. At only 6.3:1 compression ratio, a lower octane fuel will perform better in the A-4. What is really missing from modern fuels is the lead that lubricated the valve stems/guides, which I believe is one reason MMI recommends some MMO in the fuel to account for that shortcoming of unleaded gas.

My question would be how old was the fuel and was it in a sealed can? A fuel can (especially if not 100% sealed) sitting in a shed going thru similar temp extremes like a boat could allow for condensation from the atmosphere to condense in the fuel and moisture to get absorbed by the ethanol..this scenario is not usually bad enough to cause a problem, but should be considered if we are splitting hairs.