Atomic 4 dies at idle

[DCHunt]

I have an Atomic-4 on a 1972 Pearson 36 that has always been reliable. It has spent all its life in lake Erie so it is only in the water 5 months out of the year and always in fresh water.

Today I was bringing it into the dock at idle after a good sail and the engine just died. If I remember correctly it was idling along and then stopped. I don't remember it sputtering but I was too busy trying to get it restarted to concentrate. I couldn't restart the engine. Luckily I had enough headway on (but not too much) that I could glide into the dock and stop before hitting the pier.

I tried to restart the engine after it was at the dock but it wouldn't start. I checked the spark with a screwdriver stuck in the spark wire and there was a good spark. I had also replaced the ignition with a solid state ignition (Ignitor by Pertronix from Moyer Marine) 3 or 4 years ago so I think the ignition is OK. I checked the gas tank for gas and it had 10 gallons at least. Also, if there had been a problem with a vapor lock this should have fixed it. However, I still couldn't start it.

I had a spare main fuel filter so I removed the old one (it was 2 or 3 years old) and put in the new one. There didn't appear to be any water in the fuel. It still didn't start for a while. After doing some more checking and then trying to start it again, it finally started and seemed to run OK.

My problem is that I don't want to be out in the lake when the engine dies again. How can I troubleshoot the problem to determine if it is the fuel system? I had the carburetor replaced on it a couple of years ago and have not had any problems up until now. What would be the symptoms of a bad fuel pump?

Also I have a replacement fuel pump (from when the engine was new) that has a glass sediment bowl. The current fuel pump on the engine has a metal sediment bowl. Wouldn't you normally want a glass bowl so you could see if there was water in the gas?

Any help would be appreciated.

Thanks,

Dan

[Kurt]

You mention sediment bowl, so I'm assuming you have a mechanical fuel pump. Their is a checklist of how to test the mechanical fuel pump somewhere on the forum here. I haven't done it for a while, but if my recollection serves me right you disconnect the outlet fuel line (from the pump), hold your finger over the end of it and work the mechanical lever a few times until pressure has built up in the line. Hold your finger over the fuel line for a bit and make sure the pump holds pressure by making sure the mechanical lever hasn't gone slack after about 15 seconds or so.

I'm pretty sure that's how to do it.

As far as the glass sediment bowl - those are not coast guard approved and are somewhat dangerous and not recommended these days. Prone to getting broken and spilling gas everywhere - not a good idea.

[DCHunt]

Thanks for the reply Kurt. Yes, it is a mechanical fuel pump and I think it was the one that came with the engine in 1972. I think my Dad got the other, spare fuel pump at that time with the glass bowl.

I'll look for the checklist on the forum.

If I want to replace it (probably after 37 years that might be a good idea) am I better off with the mechanical or the electrical fuel pump?

Dan

[Kurt]

Well, that's a point of opinion and contention. I like the mechanical pump for 3 reasons- (1) I can rebuild it at sea if needed with the rebuild kit, (2) they are less sensitive to air in the fuel system, (3) easy to prime and check with the mechanical lever. There are some downsides such as failure of the pump diaphram can cause gas to get into your oil and you can't install the oil pressure shut off/safety switch on the mechanical pumps. I think they are really durable, though, and I check and smell my oil everytime I take the boat out anyway. I like mechanical things - the less electronics the better - just my opinion!

[dvd]

DC

You will hear a lot of different responses to this as there are advantages and disadvantages to both electric and mechanical fuel pumps.

Electric fuel pumps make priming your fuel system very easy in the event you need to do so. eg. running out of gas or simply changing an in line fuel filter, which may be the only problem you are having.

My perference is to stick with the mechanical fuel pump. A mechanical fuel pump can only pump fuel when the engine is running. The electrical fuel pump will pump fuel even when the engine is not running. So if you have a weak or dirty check valve in the carb and the fuel pump is left on for some reason it will pump fuel into the boat. Not a good thing especially if your not around.

You will probably hear a lot of different opinions on this but I perfer the safety of the mechanical fuel pump. MMI has them both readily available.

DVD

[sastanley]

mech!!

Another vote for mechanical. I added a Racor filter (and for a while had a polishing filter...currently removed while doing 'other' troubleshooting)

Earlier this summer, I accidentally left the petcock closed at the tank and ran the motor until the supply line & filter was dry (about 10 minutes). My mech fuel pump had no problem pulling fuel from the tank in my Catalina 30 and priming the entire system in about 20-30 seconds of cranking.

There is a thread on this board right now about another boat owner having trouble with fuel supply...(a C-30 I think) Looking at the electrical connections related to the safety switches, it adds another level of complexity.

edit - Dan, to answer one of your questions, I do not think glass bowls are USCG approved for inboard gas applications.

[Dave Neptune]

Pump check

Dan, you should be able to use the priming bail to check the "check-valves" in ther pump with the carb in place as the "needle&seat" should hold closed once the fuel is in the bowl.

I too use the mechanical pump and had to add a "shoe" to the pick up arm as it had worn enough not to actuate the pump adaquetly above idle, I found this out with my preassure gage!

Dave Neptune

[Marian Claire]

The MC came with an electric pump. So I have no experience with the mechanical fuel pump. The best thing I can say about the electric is that it is a “plug and play” part. I carry a spare and can change it out in 15 minutes or less. I have had a series E Facet pump die on me and when they die that’s it. A low oil pressure swith takes care of the running with the engine not running situation. Dan S/V Marian Claire

[msauntry]

The mechanical diaphragm may be easy to rebuild at sea, but MC makes a good point that the Facet elec. pump is likewise easily replaced with a spare if you plan well enough to carry one, PLUS you don't have do an oil change because of oil/gas contamination. However, going through all the troubleshooting to determine that the gasket needs replacing on the mechanical pump can take a while. The fuel pressure gauge mentioned in recent posts seems to negate this issue, though. Another thought... nearly every modern vehicle comes with an electric fuel pump. Rigging it to the oil pressure switch also means it can't run unless the engine is running.
I think its a preference for whatever each owner is comfortable with. Both have advantages and disadvantages.

My vote? Like the song says:

It's electric... boogie, woogie, woogie!

[DCHunt]

Thanks, everyone, for the various opinions on the different types of pumps. I think I will stick with the Mechanical one for now.

I don't have a polishing filter. I have the Racor as my main filter. Would a polishing filter make sense? I don't see a lot of foreign material in the gas but OTOH, the boat is 37 years old!

On the Racor, is the idea that if you want to check for water in the gas that you should just turn off the valve from the fuel tank to the filter then open the plug on the bottom of the filter and drain it into something that you can then see if water separates from the gas? How long would that take? A couple minutes?

Or is it that when I open the plug on the bottom of the filter that I should see either nothing or just water come out?

Thanks again,
dan

[sastanley]

Dan,
I think the idea is the water should separate to the bottom, however, the fuel in the filter will come out of the drain as well.

I haven't figured out a good way to just get water out without dumping out the fuel from the filter also.

Incidentally, I do not have a polishing filter either.

[smosher]

Dan, the polishing filter keeps pieces of the rubber membrane from the pump from entering the carb. I believe these flake off over time. I had this issue several years ago and there was small black pieces in the bottom of the carb when I opened it up.

Steve

[keelcooler]

Dave has a good point and I'm thinking about installing a gauge as a troubleshooting tool. How many worn fuel pump pick up arms out there causing inadequate fuel pressure resulting in poor high RPM performance?

Don,have you seen many pumps needing a shoe extension welded on?

[sastanley]

pump membrane spare storage?

My little brain always churns at work when I'd rather be on the boat...

Is there a recommended method to store a spare mech pump membrane? I wonder if maybe it should be coated in some MMO or grease or something to keep it supple in storage?

[DCHunt]

Thanks, Steve and others. I think I want to get that polishing filter. Now where can I find a fuel gauge? Is it an in-line gauge that people use or do you mount it somewhere?

Make and model number anyone??

Dan