Troubleshooting engine shut down issue

[cfergu22]

History:
We bought a 1974 C&C 30 foot MK1 with an Atomic 4 about 2 months ago. It's in good sailing condition but the PO didn't need to motor longer than 200 or 300 yards before putting up his sails so he didn't do much more than required upkeep of it. Just to note, I'm very inexperienced with engines but I'm trying to learn as much as I can as fast as I can.

During the Survey the Engine died and would not start back up, we foolishly had got distracted and left the choke out for about 30 minutes and just figured we flooded the engine. We talked to the PO about it and found out that the gas in the tank was probably around 2 years old. So we thought that between the old gas and mistakenly leaving the choke on for 30 minutes that the stall out wasn't a big problem.

After the boat purchase I drained all the gas from the tank and filled it with 10 gallons of fresh gas. After that I changed the Sierra fuel filter. We then took the boat out for 2 short trips. On those trips the engine was stalling out if we didn't give it choke the whole time. However, the engine ran better toward then end of the second trip so we assumed that the bad gas from before had worked itself out of the system.

Then we needed to sail the boat from it's previous location to the slip that we had set up. On that trip the engine ran great overall. Over a 10 hour trip we motored for at least 4 hours and it only stalled once but started back up right away.

Since it's been back in it's home location things have gotten worse. We got caught in a bad storm on the first trip and the engine died in 6 foot seas and wouldn't start back up. I assumed that all the boat heaving had flooded the engine, after the storm we sailed it back to a temporary slip. The next day it started and ran fine for us to get back to our slip.

The next 4 trips the motor has died multiple times, usually after about 10 minutes. You can hear the engine start to loose power, then within about 10 seconds it dies. One time I got it started back up with spray starter fluid and by tapping the carb but the other times I've had to wait anywhere from 30 minutes to the next day.

Current Situation:
After today's 2 stall outs I assumed that the Carb was dirty or a jet was clogged so I removed the carb to clean it. I removed the Main Passage plug and the scavenge tube to drain the carb but less than a teaspoon of gas came out. The inside of the carb was bone dry. That made me think that it wasn't the Carb after all. I checked the wire that goes from the oil pressure safety switch to the fuel pump an noticed that I was able to pull it off it's termination without much effort. Here's a picture of that termination.

What is the blue cable that's on that same termination for? I included a picture of where that cable runs too.

Could this be just a loose termination problem?
Could the fuel pump be bad?
What are some other things I should check for? \

I just got the manual from Moyer Marine and downloaded the video, so I'm going to clean the carb and see if that helps the problem. I just want to know if there's other ways I should be troubleshooting.

Thanks for your help, reading this forum has really helped me out so far in my struggle to understand how to get this engine working.

[sastanley]

Hi cferg,

Welcome to the forum.

Intermittent and random shutdowns, as I am sure you are aware, are hard to diagnose.

First, I would make sure that all electrical connections are sound. Never trust a P.O.'s work, and if a connection is loose or corroded, fix it. Sometimes, a short develops during use..a connection is corroded or loose, and as the wire heats up from the current running thru it, a short develops and the circuit fails..after cooling down, the short goes away, long enough to restart the engine for 5 seconds, 5 minutes, or maybe 5 hours.

Since you suspect the OPSS & its connections, when it shuts down again, I would use a jumper wire to bypass the OPSS (i.e. wire the fuel pump directly to the ignition switch so it is running when the switch is turned on) and see if I could get it to start again.

Dissecting stuff the P.O. did is always frustrating..pictures are great, so we'll help you through it. When you are ready to tackle the job, I might recommend a full engine electrical circuit overall, so that all the connections are new, wires new, circuit runs known by you, etc..it took me 4 years to get comfortable enough to do that on my boat.

Where does that yellow wire w/ fuse holder go? It is tapped into the alternator output?!? It looks to me that it is possible the blue wire is connected to the starter..possibly to provide power to the fuel pump during cranking..some starters have a terminal that is hot (+12v) ONLY when cranking.

edit - Based on what I see, there is a lot of 'handiwork' that may need to be remedied. The P.O. of my boat had all kinds of electrical 'band-aids' everywhere.

[keithems]

i have a c&c 30 also -- fab boat

welcome to the forum

if u read my recent posts, you will see that i had a very similar problem. it was fuel contamination. i think once u get it, you can clean your carb, change filters for ever, and you'll just gunk them up again.

how old is your tank? what's it made of? mine seems to be aluminum and i'm wondering if yours is also. on mine, i think i can remove the plate where the fuel gauge sender wire goes in and then try to suck out the gunk. i don't know if that will help. likely not...but luckily in our boat it looks like the tank will come out easily and then it can be steam cleaned or replaced with a plastic one for about $150.

meanwhile. the best way to diagnose and see if i'm correct is to hook up a clean [preferably new] outboard tank with all fresh fuel. make sure your carb and filters and lines are clean before you do. if it runs well, like mine does now, then that was your problem.

fyi -- these a4's are very durable and will take a lot of abuse. if it's not tuned up perfectly, etc., it will still run. the weak side is the fuel system. it was not designed to run today's gas. so you cannot have any leaks or contamination re. the fuel or it will not run. or worse, it will run long enough to strand you where you don't want to be.

let me know what happens.

[ndutton]

The bigger picture

For those with bona fide fuel contamination problems, once you chase it down and clean it up remember it came from somewhere in the first place. There are really only two possible mechanisms:

• Contaminants allowed to enter the tank
• Deterioration of fuel hose

Contaminants allowed entry
These can come from a variety of sources: deteriorated O-ring seal on the fuel fill plate, pumping in already contaminated fuel, perhaps even incursion through the tank vent (rare in my opinion). There's not much point in cleaning things up and then putting more contamination in the tank.

Deterioration of fuel hose
The common scenario here is ethanol use in old non-ethanol rated hose. Same advisement as above, why clean the contamination only to have it continue? All our fuel hoses should be rated for alcohol.

It's popular to blame ethanol as a contaminant itself or as causing the contamination. Admittedly, it has some properties that aggravate existing conditions:
Crud in the tank
Previously inert crud in the tank is now rendered 'ert' by the dissolving action of the ethanol returning it to the mix. Remember though, the crud was there to start with and came from somewhere outside the tank.
Fuel hose deterioration
See above. No need to repeat.
Moisture absorption
I cannot speak from any experience here so I won't try. In my local climate it's not a problem but I can't say for others. I will offer this - my Dad worked in the aircraft industry his entire life and I remember him saying planes are always stored with the fuel tanks full. Less air space means less humid air and less moisture. This was before the blended fuels we enjoy today. He said also that due to moisture present in the fuel from storage tanks, trucks and infrastructure fuel delivery systems it was possible to draw off a cup or two of pure water from the bottom of a plane's tanks.
Dissolved fiberglass tanks
Common in power boats with fiberglass tanks, virtually non-existent in sailboats.

[keithems]

good article, but it does not mention a major problem in 30+ yr old sailboats:

per jeff, the local west marine engine guru....the tank itself begins to deteriorate -- or at least the lining does, likely from the ethanol -- he says not just in steel, but aluminum -- even plastic! he told me that even 2 yr old plastic tanks are vulnerable and they had to junk all the ones in inventory. [apparently, current plastic tanks are more resistant]

when i bought my boat in 2007, the state sticker on it was from 2002. meaning it sat with a partially full tank for at least 5 yrs! and also....because the pick up tube stops an inch or 2 above the bottom, the concentration of water and gunk can only increase over time since water is heavier than gas and always goes to the bottom.

[i flew gasoline powered aircraft for quite a while, and they all have quick drains on the bottom of every tank, which you must drain before every flight -- or at least after every fill up!]

and once that concentration goes to a certain level, things can only get worse. adding fuel to dilute it or products like e-z sorb -- as i did last week -- only insure that you'll move junk into your carb or dirty your filters. so as others advised me, eventually the tank has to come out to be rehabbed or replaced.

[67c&ccorv]

This is a shill for the new improved "Stabil" fuel additive but it does contain some useful information about the effects of ethanol blended fuels on marine fuel systems;

http://www.goldeagle.com/UserFiles/file/Ethanol%20411/Ethanol%20--%20The%20Good,%20The%20Bad,%20and%20the%20Ugly.pdf

And here is Mercury Marine's view;

http://www.ejmertaughboatworks.com/ethanol.pdf

[ndutton]

per jeff, the local west marine engine guru....the tank itself begins to deteriorate -- or at least the lining does, likely from the ethanol -- he says not just in steel, but aluminum -- even plastic!

Lining?? Forgive my ignorance but what lining??

Dating back to 1971 I've been involved in the purchase, installation, construction, design and modification of fuel tanks made of steel, aluminum and fiberglass in one way or another and not a single one had a lining of any sort. For metallic tanks, wouldn't welding fittings and seams destroy a lining?

For my own education I'd like to know where Jeff got this information.

[keithems]

well i've never been involved, so the reference to lining may be my stupidity.

maybe there's a coating in some tanks?

i dunno -- i just know -- now from experience that very little lasts forever and if u purchase a 30+ year boat for a song, as i did, you should be prepared to replace a lot of things...let's see....in my case it's been sails, motor, interior, stuffing box & hose, cutlass, windex, mast wiring, etc., etc. -- and now the tank.

again, in the c&c 30 pulling the tank is not so bad.....and it's better to spend 150 than constantly rebuild the carb, change filters, blow out the lines, and call towboat u.s.

and overall....not really all that bad -- 30,000 boat for 1800...with good rigging, mast, hull & deck,winches [2 self tailing, geared, 2 geared], and roller furling.

so it goes....

oh -- and re. the stabil and other formulations... they may prevent problems if you're starting with a clean tank and fresh fuel, but they don't undo years of crud accumulation.

the good news.....because the junk and water tend to sink to the bottom, and i don't think i had true phase separation, i was able to pour off most of the clean but water diluted [cloudy] fuel on the top and burn it in my dodge caravan.

[Mo]

HI Guys,

I will relay what little I know of this stuff and I know most already are aware of it. I don`t have to deal with ethanol YET and hope I never do. What knowledge I have has come from this forum and a few other reads....nothing spectacular.

Over time gas can leave a deposit on the inner aspect of a gas tank, especially if sitting for a period of time. Typically, this didn't pose a problem as the gas being poured in the tank was the same chemical make-up for years.

With the introduction of Ethanol some problems began to surface. Ethanol apparently breaks down the "lining" or "coating" of crud. This results in deposits afloat in the gas and drawn downstream by the pump. Filters help, however some inevitably gets past the filters, and ends up in the carb. This may caused recurrent problems.

There is also the issue of Ethenol breaking down rubber hoses. Newer hoses have been developed not to break down with exposure to ethanol, however, even the fill hose on older boats can present a problem and cause a problem of dirt in gas.

This doesn't address the issue of old gas /bad gas....that just simply needs to be replace and the tank cleaned. In the case of crud via ethanol reaction....the tank should be cleaned and all rubber hoses replaced with new versions resistant to ethanol.

[ndutton]

Why didn't cars have these problems?

[keithems]

just speculating -- i'm NOT an expert....

1. auto motors are designed to run on ethanol -- tanks may be designed for it also

2. autos have electronic fuel injection which can adjust and tune mixture to optimal

3. the a4 does much better if your marine fuel is e-10 free; i don't think that is available around here -- meaning most marine fuel is really auto fuel

4. i'm not driving a 1976 auto whose motor and fuel system was designed in 1950 or earlier.

5. the fuel in my tank is always fresh -- i refill it at least weekly

5a. my car never sits unused for half the year

6. most car fuel tanks sit on the bottom of the vehicle and are exposed to slush and salt, etc., and tend to rust out at least every 10 years-- i suspect the e-10 helps insure that

[keithems]

actually, i didn't have major fuel / tank issues before my a 4 broke her cam last summer. because i knew it would be a while to r, r, and r it, i ran my outboard off the remaining fuel in the tank and left it dry for the winter. -- or so i thought -- in reality i left 2" of concentrated water and gunk in the tank

then this summer once the a4 was back in, i poured a few gallons of auto fuel in to get started -- didn't want to fill it in case i had to pull it -- and i think it was evening after the marina pumps were closed. that's when the fun began.

so if i had been continually using the tank and had left it full and added stabil for the winter, i may have been ok. or not...seeing as the gunk / water concentration is always increasing and acting on the tank surface.

i do think that if you start with a clean or new tank and fresh fuel and use stabil or other additives, things will be ok.

[ndutton]

But at the time of transition there were many autos with older technology and even a few still around with carburetors. I don't remember hearing a peep about these sorts of problems.

My ancient Briggs and Stratton powered lawn mower has no problems and it sits for prolonged periods. My 25HP carbureted Yamaha outboard sits for months with no problems either. My 1979 Honda 750 - same thing.

This raises one of my favorite questions: why some and not others?

[keithems]

that's always true -- some and not others...

we've all known or heard of smokers living to 90 with no health problems -- but it's a matter of percentages

i had lots of problems running my lawnmowers in the late 90's and early 2000's -- till i got smart -- now i rent an apt and let the landlord cut the grass so i can go boating!

plus u live in california where i think they always had to engineer motors to more exacting requirements.

like i said, i had problems when i first got this boat, but they cleared up and everything was ok till i let the tank sit empty for a year. and my fellow c&c 30 owner who started this thread also is dealing with a situation of long non use with gunk buildup.

also...may help to stick to marine fuel -- the boatyard where i store and service my boat claims their fuel has no ethanol -- which i doubt, frankly, having seen the truck deliver it, and the marina i berth at does add valvect to their fuel, which is supposed to prevent problems and likely does if you don't have them to begin with.

i wonder if i started things off by using auto fuel this year to get started?

anyhoo, the die is cast, and now that i'm using the outboard tank, a4 is running well, and when i have the chance i will pump out my ship's tank if possible or r& r it if necessary. sure beats going out on the a4 5 times in an evening and returning 5 times on the johnson 9.9.

[Antibes]

I had all kinds of problems with my tank over the last two years and I buy most of my gas at my local marina with Valvetech added, Currently $5.25/gal. I don't think that additives make much of a difference for most problems, of course excluding MMO.