Atomic 4 Troubleshoot Assistance - Please

[Anonymous7500]

I am looking for some troubleshooting assistance with the Atomic 4 that is in our new-to-us 1977 Pearson 30.

The back story:
-1977 Pearson 30
-Located in south west Michigan (seasonal use)
-Used minimally past few seasons, less than 3 hours engine operation per season
-Received tune-up July 2011
-Added fuel in May 2012 at launch, 16 gallons to 22 gallon tank.
-Consumed approximately 10 gallons this summer, mostly around 1000 rpm.

The engine started immediately in the spring with little choke or throttle and ran flawlessly. In the past month starting has become more difficult requiring some combination of choke and throttle. This past weekend it was near impossible to start and took a significant amount of time to warm up and operate smoothly. About 2.9 miles into our 3 mile motoring to get to Lake Michigan, the engine speed slowed and quit without a sputter.

I attempted to restart a few times and could only manage to fire the engine with nearly full choke and about 3/4 throttle. It quit as soon as the throttle or choke were reduced. Given the proximity of the pier, restarting the engine was given a lower priority to keeping the boat off of the pier.

Today I replaced the fuel filter which was filthy with residue and was new in July 2011. I was only able to get the engine to start and run with full choke and about 3/4 throttle again today. As soon as either the choke or throttle are reduced the engine quits. I also probed the fuel tank and could feel significant sediment on the bottom.

I am thinking that I need to find foreign matter in the carburetor. Any other suggestions will be appreciated.

On a different note, the first power boat to enter the channel, "Slurpy", offered assistance and towed us back the three miles to our slip. Our slip was about a mile past theirs. Thanks to them!

[Nemo55]

Your fuel supply is totally compromised, as you know already.
Your Carburetor needs taken apart and thoroughly cleaned.
You need to totally clean that fuel tank out and flush the fuel lines , and add a large gravity drop filter before the motor.
Then you should be good to go,anything less and you are courting disaster.

Just my opinion of course..

[Acushla]

I fully concur with Nemo55 comments, the root cause is a dirty tank. The tank, fuel lines, filters and carb all need to be pulled down and cleaned before any more attempted voyages.

Acushla

[Ex-Calif]

Not sure what assistance you need. You nailed it. Dirty fuel.

The carburetor is totally compromised. It needs a complete tear down and overhaul. You'll never get it clean in the assembled condition.

[Anonymous7500]

Originally Posted by Nemo55

Your fuel supply is totally compromised, as you know already.
Your Carburetor needs taken apart and thoroughly cleaned.
You need to totally clean that fuel tank out and flush the fuel lines , and add a large gravity drop filter before the motor.
Then you should be good to go,anything less and you are courting disaster.

Nothing wrong with hoping that there was a hidden reset button, right? Seriously, I knew what had to happen when I felt the grime in the bottom of the fuel tank.

Thanks for the confirmation.

[RicknSue]

Our new to us Pearson 30 had the same issue (as did my buddy's Erickson 27 last year), while your at rebuilding the fuel system- add an electric fuel pump and regulator and eliminate any pump issues. I used Holly stuff(high quality and available through any auto parts store).
Moyer marine has all the carb stuff you need.

[callmecrazy]

I didn't have to deal with it, but the previous owner had similar problems that were ongoing. After a few years of tank cleanings, filter replacements, etc... He finally bit the bullet and replaced the fuel tank and all associated parts. That was about 4 years ago and it hasn't had a problem since.

[Florida Mike]

I would get one or two 6 gallon outboard tanks and the associated plumbing. Always run your engine dry at the end of the day or weekend. The point being never let fuel stood in the carburetor for more than a couple of days. At the end of the season take whatever fuel is left and put it into your vehicle. Take your old tank out and throw it away make a shelf for your 6 gallon tanks. Just my two cents, Mike.

[phorvati]

Originally Posted by Florida Mike

Always run your engine dry at the end of the day or weekend. The point being never let fuel stood in the carburetor for more than a couple of days.

There will always be fuel in the cab fuel bowl. run dry does not mean no fuel left in the carburetor. You should fog it before storage, and also there is a fuel bowl drain plug. Fogging would coat the nozzle passages. Drain would ensure no fuel is left in the bowl to gum up.
I think long storage and lack of use caused the problem. No use is worse then too much use.
Ive always had problems with storage to a point where my practice was to take the carb home over the winter, drain it, blow carb cleaner through all passages. Keep it in room temperature, dry place.
Moyer sells carbs, if i remember correctly around 160$. I got one in 2005 and lasted me till last year at which time I re-powered with diesel.

[hellosailor]

Anon-
I would contact Moyer Marine and see what manuals they have available, they are the goto guys for A4s.

Any carburetor needs to be torn down and rebuilt about once every five years. So even as a routine maintenance matter, you want to get a major rebuild kit and a gallon of gumout, and tear down the carb. Rebuilding them is mainly a matter of being clean, careful, and patient. Work on a large flat area, put down an old towel so small parts can't bounce away, use a digicam if needed to make sure things go back together in the right order.

The traditional old coil ignition system often needs a new coil every ten years, so yours may be due also. Do a full tuneup (points, rotor, cap) while you're at it.

And when you say hard to start, does that mean your starter is not spinning it up? Or the engine is not firing? With any luck the major tuneup and carb rebuild are all you need. The A4 is very much the same as any automobile engine was in the 60's or 70's, no great mysteries in it.

[donradcliffe]

The root cause is probably ethanol in the gas you put it in the tank.

[Anonymous7500]

Update: 8-28-2012

The carburetor was cleaned, but wasn't terribly dirty. The spark plugs were replaced and looked pretty awful. The inline filter was also replaced. The engine is back to running smoothly.

I was informed that it would be best to remove the fuel tank to clean it. This requires removing the engine. This will be my winter project...trying to find a way to get the tank out without pulling the engine. I will be replacing the tank with a Moeller unit.

Does anyone have experience getting a tank out without pulling the tank? I am not opposed to destroying it in the process.

Is there an additive to counteract the negative results of Ethanol content?

Thanks!

[Nemo55]

As to the removal of your tank, without knowing the particular geometry of your setup,,i cant be very helpful, I would suggest pumping it dry and use soak rags,,then warm air to get rid of leftover fuel.
Then cut it out in sections if you can get at it.
As to the fuel with Ethanol, i think you may find that Ethanol is added only to the Mid grade and low grade fuels,,,Premium fuel doesn't seem to use it.
The long term is of course switching all of your soft seals in the Carb fuel system to Ethanol grade material.
Good to hear you got her running again,,,,now go overboard on filters,,,especially gravity canister types.

[hellosailor]

"Is there an additive to counteract the negative results of Ethanol content?"
One from Starbrite, one from Stabilant, several brand names offer them. There are also a number of gas stations and marinas offering "pure" ga$oline:
pure-gas.org : ethanol-free gas stations

but as Nemo says, the solution is to rebuild your carb, and if necessary any fuel hoses, so they work with it. A carb should be rebuilt every 5 years or so anyway, and fuel lines replaced from time to time as well, so that's really just routine PM.

[Anonymous7500]

Well, I can't think of a good reason to not replace the fuel lines when the tank is being replaced. That will be added to the list of things to do this winter.

As far as fuel filters, there is currently an inline filter and a gravity canister filter down line from there.

Thanks again for the input.