| Author |
Message |
    
Sal
| | Posted on Wednesday, January 08, 2003 - 10:37 pm: | 
|
Towards the end of this years boating season
this engine would bog down in full throttle
and then intermittanly regain power. Had a dual battery system which I disconnected thinking an electrical problem was to blame. Added dry gas to the tank thinking perhaps there was some water in the gas.After I hauled the boat, I noticed the water separator was much rustier than usual and it contained a great deal of rust debris and water- so I gather perhaps this was the problem. What other troubleshooting should I perform and how often should water separators be changed. Thanks so much for your reply. |
SEAN HALL
| | Posted on Thursday, January 09, 2003 - 01:16 am: |
|
I DON'T KNOW MUCH ABOUT OUTBOARDS BUT I DO KNOW THAT WHEN OUR INBOARD V8 ACTED LIKE THAT IT THE CARB NEEDED TO BE CLEANED AND POSSIBLE REBUILT. I DON'T KNOW IF THAT WILL HELP YOU OR NOT |
Jon
| | Posted on Thursday, January 09, 2003 - 12:20 pm: |
|
Sal,
As for the batteries - there's a million ways to do a dual battery system, but there are only three ways I can think of that the batteries could hurt anything electrical. The first is wiring them backwards; the second is putting two 12 volt batteries in a series (24 volts - ouch!); lastly, if you disconnect the batteries while the engine is running, it can destroy charging components.
As for you engine - it sounds like you have SERIOUS issues with water getting into your fuel system. The first thing I'm wondering is where the rust and all the water is coming from.. if it's just that the water separator is rusting - replace it; if you have a steel fuel tank of some sort, it's time to get rid of that and replace it with plastic, stainless, or an aluminum tank(s). If there is anything else made of steel in your fuel system up to the engine, replace that too. What I'm saying might be a little harsh, but there just isn't any tolerable amount of rust in the fuel system of a boat.
Sometimes a bit of water can enter the fuel system by condensation. If you are not keeping the tank(s) full and/or have a metal tank, sunlight can heat things up and form droplets of water. It's also possible to have water getting in from a vent or breach somewhere in the top of the tank.
Bogging can be electrical, but with water in the fuel, there's very little reason to suspect an electrical problem at this point. Bogging is usually caused by a lack of fuel (or lack of fuel that burns) getting to the engine; if the jets in your carb get clogged, with even a tiny spec of garbage, water, or varnish left over from evaporating fuel, as you advance the throttle and open the butterflies the air flow will be there, but not the fuel. A lack of fuel causes a lean mix, which creates the bog. Water in the fuel, in general, will also cause a bog as it doesn't move through the carb like fuel and won't burn.
The only real solution for you is going to be to take all fuel system components out, carefully inspect, and then flush/drain them completely - replace anything that is questionable or cheap enough. If it's about time to replace the fuel lines & primer bulb (say it's around 5+ years old), do that now. I'd think about replacing all the fuel lines in the engine too, but no matter what, they need to be cleaned after what has happened. All fuel filters should be swapped out w/ new ones too etc.. etc.. Lastly, the carbs are going to need to be completely disassembled, carefully cleaned, and rebuilt.
As for how often to change the water seperators; I've got a couple hundred hours on a rayco, and I'll replace it becuase the outside is corroding, but it wouldn't need it otherwise. My belly tank is about 40 gallons and it's plastic, I fill it after ever trip and haven't ever found evidence of water in the fuel.
Oh.. and the dry gas - NEVER use dry gas in an outboard. There are a few problems with it, the first is it's a solvent and will dislodge chunks of fuel varnish, sending them up the line toward the carb (can end up clogging a carb); the second problem is that it will weaken or even dissolve certain rubbers; lastly, dry gas is alchohol, which is a solvent for oil/fuel - 2-strokes are lubricated by fuel/oil. A marine fuel stabilizer is a good idea though, I add Penzoil marine fuel conditioner/stabilizer every fill up.
Be sure and at least fog those cylinders if that engine is sitting, as it's got some moisture in it now. Tell us how it goes,
Jon |
Rick
| | Posted on Thursday, January 09, 2003 - 06:04 pm: |
|
Sal,
Jon is right on the money regarding your fuel system, but I would not rule out an ignition problem. Your engine has four coils with four grounds, a powerpack, harness, leads, spark plugs, etc. If the intermittant bog is instantanious it could be electrical. I would inspect the wiring and components for cracks, chafed wires, corroded connectors shorts etc. Pay special attention to the ground connectors. Although intermittant problems seldom show up during testing, I would still do a spark check of all cylinders at cranking speed. It just might show you something. Even if you find and correct an electrical problem, I would still service the fuel system as Jon outlined. By the way, you might as well check the compression while you have the hood off. Good luck
Rick |
alan
| | Posted on Friday, January 10, 2003 - 12:11 am: |
|
I have a 1985 OMC 120HP. I am not a mechanic, so I would listen to a mechanics advice w/ priority.
My limited experience: If the miss is a quick miss and then it quickly picks up, and dose it consistently, I would say it sounds like an electrical problem. Sometimes, the powerpack 'goes' - slowly and the symptoms seem fuel-like. If you think water is in the gas, then by-pass the onboard fuel system and use a 6 gallon test tank w/ new fuel and oil.
The electric system is a bitch to trouble shoot unless you know your stuff. I was lucky enough to get the powerpack thing after a whole summer of doubt ( and engine skipping ) and a lot of advice from different people.
If it is a ' sneeze, it is definitely a fuel thing. But a complete cut out would lead me to electric... Good luck and don't get frustrated - you'll figure it out - or pay someone to do it 'cause your a boat junky like all of us !
- Alan |
Bubba
| | Posted on Friday, January 10, 2003 - 06:24 pm: |
|
One easy way to diagnose is to take the boat out and run it; when it "bogs dowm", push in the key (choke)and if the motor picks up, you will know that you have something undesirable in your carburetors. That motor doesn't have a choke, it is a primer that pumps raw fuel directly into the intake manifold bypassing the carburetors. If the motor picks up when the fuel path goes around the carbs, there you have it. |
Sal
| | Posted on Friday, January 10, 2003 - 11:28 pm: |
|
Thanks to all that responded to my dilemma.
Will try troubleshooting in the spring. |
Chris Kemp
| | Posted on Friday, February 07, 2003 - 09:37 pm: |
|
sal,
just check compression on all the pistons....I had a problem on a 78 evinrude .....Head Gasket, the water jacket was leaking into the cylinder causing the bogging and hesitation at high speeds...it also shut it down, so check the compression, or have a mechanic check it.
It's a bit late since the original postings, but it sure isn't spring yet either!
Chris |
|
