Outboard Issues, Part II

[Brian D]

The saga continues!

FAILURE

What I thought was success was in fact a tom-foolery on the motor's part. It knew I would be elated so it worked until the next time I fired it up. Failure.

So lets recap what I have done so far.

1. Changed out the fuel connector at the motor and the hose connecting to the motor. Fuel is flowing as I can see it in the in-line fuel filter in the engine.

2. Used a Combustion Chamber Cleaner in the carb. The spray was entered via the intake. Some smoke appeared and the first indication was all is good. Engined fired up with choke on. Closed choke and engine continued to work. Shut off engine, flushed, went home.

3. Came back two days later and fired up engine. It worked for about 10 minutes then died. Could not get it started with choke in. Pulled out choke and it started just fine. Push choke in and it dies.

4. Purchased a can of Sea Foam Spray. Sprayed the carb and the engine worked again with choke in. Lots of smoke (now I must say that this is a marketing hype. The smoke is caused by an ingredient in the solution, not carbon burning as the can states.) Engine ran for about 10 minutes then died.

5. Came home and read some more. It was recommend to fill the carb with Sea Foam and let sit over night. Went back to the boat and did just that. Fill the carb via the fuel hose from the fuel pump to the carb.

6. Went to the boat this morning. Engine would not start until fuel replaced the Sea Foam. Engine started but then after about 10 minutes failed.

At this point I believe I flooded the carb as the engine will not start. I pulled the plugs and they were fouled. Cleaned them and the engine will not start. Pulled the fuel line from the pump to the carb and started to test for fuel flow. Fuel is flowing out of the pump.

Here is the most interesting part. When the engine is running and I just touch the choke to open it, the engine quits. Even the slightest push forward and the engine stops. It has to be the choke mechanism and I am wondering if it has any linkage to the way fuel flows from the bowl to the cylinders.

Next, it is not "bad" fuel. I put in 20 gals in March for a trip to Dana Point and added Stabil. On the trip the motor quit. Also, a neighbor had a can of fresh gas and I tried that. The fresh eventually replace the possibly bad gas, but there was no change.

Another mention was an air leak. But where, and why would the choke have anything to do with that? I really think the fuel flow is being interrupted by something. Maybe a piece of debris in the float is getting up into the main jet.

I tried to take the intake off the carb to take a look but the area was too tight to insert a 10mm wrench without taking off the fly wheel. Actually dropped a small socket into the bottom crowling. That is is going to be fun trying to retrieve. I checked to see if there was going to be any issues. None that I can see right now.

OK, some more thoughts. And yes, I will eventually bring the motor home and pull the carb. Need to get the service manual for this motor.

 

[Chief RA]

Main jet is not clean and bowl probably letting gas lauquer film loose up into the jet. Give it up and pull the carb, clean and put back on, Common for our gasoline. Run it dry when your done with it. Chief

 

[caguy]

It's the low speed jets. The crab needs to be taken apart and cleaned. There should be small lead plugs that have to be removed so the jet can be blown out. When I took my OB to a shop in Ventura I got to watch them take the carb apart and Ultra sound clean the carb for about an hour. I also switched to Av gas for that OB.

 

[Winkfish]

Brian, try the Sea Foam treatment I posted in the other thread. Even if it doesn't solve the problem completely, you'll have a clean engine.

Also, maybe carbs or jets are damaged and affecting fuel flow?

 

[seadaddler]

Sea Foam

I found out that once the outboard starts acting bad it's too late
for sea foam or any other carb cleaning and I use sea foam all the time
but when ever my Yamaha started running bad I tried adding sea foam and other hoping it would clean things and let it run good but guess what,I never had any success at all and I had to always take the carb off and clean the jets with great running outboard after that.
Sorry but yes sea foam with every tank seems to help avoid problems for pretty
long time,my problems seem to appear after leaving the out board for a month or 2 and than it just doesn't like to run very good.
I will soon be putting it away and will run it dry and add extra sea foam for the last run before storage.
Nick

 

[Winkfish]

Not trying to say that Sea Foam is magic, but it works pretty darn good. I got the treatment process from mechanic types on an outboard motor forum. It worked on my 1985 Merc 90 hp and on numerous others' motors.

I'm only suggesting doing this relatively cheap and easy thing before doing the more difficult ones.

 

[Winkfish]

And the treatment was indeed recommended for when the motor started acting badly, the reasoning being that the buildup of carbons could be causing or contributing to the problem.

 

[Stu Jackson]

Brain, IIRC, Donalex suggested what you need to do in your last go around on this subject. Good luck.

 

[Brian D]

Well, I tried the Sea Foam shock treatment. It only works for a short period of time. I think, as others have pointed out quite insistently, it is time to pull the carb. I cannot take the motor off the boat so it has to be done dockside. The carb bolts are in a very tight location and getting to one in particular means possibly taking off the flywheel. I do not have the tools to do that. So I am going to try something else. We will see.

I think there are two bolts, linkage, and three hoses that need to be removed then the carb should be in my hands. I can say, without reservations, that I am scared ________ (fill in the blank). A new carb will set me back around $300+. But that is cheaper than taking it to a repair shop.

So this week will be a test run on seeing if the tool I purchased will fit in the limited space. Like I mentioned above, I have already dropped one small tool in the lower crowling. I have to take that off to get it. Unless I can find one of those goose neck cameras and a long slender pick-up tool.

Fingers crossed.

 

[Stu Jackson]

Brian, why not re-read your last post?

http://forums.catalina.sailboatowners.com/showthread.php?t=162807

Those guys who know said remove the carb.

 

[Chief RA]

Stu, there is nothing else any of us can do short of going over and removing the carb. I am done. Chief

 

[Stu Jackson]

Curious

Brian, why can't you take the motor off the boat?

 

[thinwater]

a. remove the carb and clean completely. With practice, it is a 15 minute job, which suggests I've done it too many times. But honestly, small boat carbs are simple. Remove the bowl, spray everything with carb cleaner, let set, and repeat. Do not disassemble further than you are comfortable, but do be certain to let the float drop and spray the needle and seat well. Sometimes the needle tip gets worn, it will stick, and replacement helps. Make sure you get ALL of the solids out of all of the corners of the bowl. If there is any evidence of corrosion (white or black spots) in the bowl they can cause trouble (the solids plug jets). An additive like Seafoam, Biobor EB, or Merc Stor-n-start (I did a bunch of corrosion testing for a mag and these are the best) will stop it.

b. Keep the tank full and the vent CLOSED when not in use. The less air and humidity see the fuel the happier it will be. This is far more important than running the engine bowl, based on testing.

c. Don't run the carb dry on a regular basis. This is a damaging urban legend that just won't die, even though operator manuals often advise against it. It is ONLY for extended storage and is ONLY mentioned in that part of the manual (most brands--some figure small engines are used so seldom they'll just advise you to do it all the time). I'm sure someone will object, but hear me out. When the carb is "run dry it 's only about 80-90% dry. That guarantees that what remains will dry and turn into gum. On the other hand, if the carb had been left full for a few days or a few weeks, the way we did with cars for 60 years, the varnish will stay in solution and pass in the first few minutes. I leave my carbs full, leave my boat for weeks in the summer, and generally it starts on the first crank, proof that the carb had not evaporated down. The PO, on the other hand, ran them dry, wore out the hose fittings, and gummed the carbs a ton. Life was better after I cleaned them (twin engines) and stopped draining them.

d. If an installed tank, either keep it full or add a vent fitler. They really help keep dry, stable fuel.

e. Don't complain; at least your motor isn't in a well. I learned to do this one while underway!

 

[Benny17441]

And the saga will continue until you pull the carb, take it apart and clean the jets and let the body and parts soak in a strong carb cleaner overnight. Like Nick said "once the outboard starts acting up is too late for Sea Foam...." Your consideration about purchasing a brand new carb is a valid one usually taken after a couple of cleanings have not solved the problem. The thing is you still will have to remove the carb to install the new one so you might as well do a good cleaning and see if it works. Take your time removing the carb for the first time taking notice of where everything goes. I would set some kind of net around the working area to catch any falling parts or tools. The best remedy to prevent the problem is to run the engine frequently, at least once a week

 

[Chief RA]

I don't run my carb dry each time I finish for the day or week but if for a month or winter I do. Lacquer content is minimal when run 90% dry, thus little or no jet blockage. Chief

 

[Brian D]

I will attempt to pull the carb day after tomorrow. Have my fingers crossed that this should go easy.

 

[mr c]

I will attempt to pull the carb day after tomorrow. Have my fingers crossed that this should go easy.

Pump the fuel line bubble til hard. Start the engine again. If the pump bubble in the fuel line doesn't stay hard when the engine is running there is an air leak. According to your first post you replaced the fuel line connectors. Happened to me. It was very subtle. After ten minutes the engine died. It stayed running when I pumped the bubble while the engine was running. As soon as I stopped the engine ran out of fuel. If that doesn't work the carb in the problem. Like everyone else said take carb off and clean.

 

[seadaddler]

Clean

I never did much carb rebuilding on cars back in the old days but
I decided to give it a shot cleaning the carb on my 8hp yamaha and
if I screw it up I will pay to have it fixed.
It really not that hard just remember where every thing goes maybe
take a photo but I did not but the real hard part is to take the jets
apart and clean them or just blow out with compressed air and that
is the part that counts,my 8hp has 3 jets to be cleaned and use a
good carb cleaner on all the parts,the jets are brass color and they
have a slit for a flat small screw driver and unscrew them out and
blow with compressed air and I also use a very very fine wire to clean
out the jets and soak in carb cleaner before putting back together.
I have had to clean my carb 3 or 5 times so learn to do and get good
at it for future times when it runs bad again.
Nick

 

[CarlN]

First - are you sure the possibly bad gas is gone? I once got some bad dinghy gas in the Bahamas. After two US tankfuls, it was still running rough. I finally had the tank flushed and used AV gas for a month (see below)

If the gas is known good -- I'd replace the carb. While the part is expensive, changing it is quick and you don't need to be a great mechanic. How many hours is the cleaning exercise going to take? What if it doesn't work the first time? Or the second?

In New England, the shops always now use an ultrasonic cleaner for hours or even overnight. The carb cleaners alone just don't work.

In my experience, cleaning a carb usually gets the engine going but the fuel problem will return - and quicker than you'd like.

Finally, AV Gas is now available by the quart through Home Depot - it's about $5 a quart but it seems to fix all sorts of mysterious problems. Cheaper than a mechanic. Especially good for dinghy engines that don't go through a lot of fuel. And you can leave it in the tank with no worries. If I don't use ethanol gas in a month - it goes in the car tank.

http://www.homedepot.com/p/Unbrande...-94-Octane-Ethanol-Free-8-Pack-6208/203528942

 

[Chief RA]

Carlf: ridiculous! Chief