this 130 has a mind of its own

[Tractor-Tug]

(1991 130, a very unliked stepchild)

after finally thinking i solved all of its issues and a hard day of running sunday, and running it for 15-20 minutes monday night, the engine is back to its old ways this morning. last night i went to the boat, and started it up. took a walk up to the car, and brought down my four 5 gallon gas jugs. shut the engine down, and restarted it. kept dying at idle, after about 20 seconds, but if its choked will stay alive. still had NOT added new gas. checked the racor, just a little water. added the new gas, same problem.

this is really killing me. the engine did this before my last carb rebuild/cleaning last week, so im assuming somehow the carbs must be contaminated again? seems like a long shot, but who knows these days with this engine, it has a mind of its own.

if i let the engine start at about 1700-2000 rpm it will usually run indefinately, although occasionally it requires a shot or two of choke to keep it up. essentially, the engine must be leaning itself out, right?

any ideas? i got a spark shock when i put my hand on the starboard thermostat housing to check the temp, it was a pulsed shock so i assume definately from the ignition system. any thoughts that it could be ignition related?

i think it will be time for a new fuel injected 4 stroke if i have to rebuild these carbs again; i'm not rebuilding carbs once a week all season.

[smokey]

I'm a bit new to this site but I've been around motors all my life. You say you got a shock when you touched the thermostat housing. No mater were the shock came from it's a problem. And if this is a problem that comes and goes I would definitely suspect electrical. Make sure your coils are not loose. clean and dry every thing from the coils to the cylinder head. Some how the spark is going were it should not. check the wires and spark plug boots for cracks.
I hope that helps a bit.

[jb123]

run your motor at night and look for arcing in that area.i have an older pro-v and the 6 coil leads were arcing out on eachother. are your plugs new/newer as if you have one bad the spark STILL needs to go somewhere.you may want to idle up your motor and pull each coil lead one at a time to isolate the culprit.

[Tractor-Tug]

on a hunch since these were the same symptoms i had a week or so ago they went away with a carburator cleaning, i went ahead and cleaned them again tonight. once again, they were full of junk *looks almost like ear wax?

i cleaned them out good again, and put them back on. engine runs the balls, but for how long is the question. hopefully this isn't a weekly thing, as i need to get back on my tug and pay the bills, and would like it running for my brother when i'm bumping up against ships.

the water seperator is new (sierra) and the engine filter is obviously there. my question is do the racor brand filters/housings filter the fuel better, or are they only beneficial out of convenience? obviously its all we use on the tugs for our fuel oil, but i'm not familliar with the gasoline ones.

this ethanol fuel is a pain, my uncle is having trouble as well lately with his EFI engines once he switched over the ethanol blend; its all we have around here. i want to think it may be cleaning my tank and helping stuff up the filters letting some water get by.

[Ken]

T-T,
You are exactly right about the ethanol.
From what I have read about it, the ethanol can break loose particles in the fuel tank and fuel line that pure gasoline won't.
Yamaha has recently come out with a service bulletin (oops - you already know about that) recommending a 10 micron filter/water separator.
But, also, I'm thinking maybe the ethanol is breaking loose particles of trash that is on the downside of your Sierra filter - from there to the onboard filter, to the fuel pump, and then to the carbs - could be.
Let us know how you come out [img]smile.gif[/img] ,
Ken K

[Tractor-Tug]

today it was really great again, that fuel primer bulb decided to start malfuctioning. one more little problem taken care of. also installed a new 10 micron filter. the older ones were 30, right?


i started noticing quite a bit of unburnt fuel in the exhaust, so i checked all of the plugs. the lower port plug smelled of fuel unlike any of the other plugs, and the engine ran the same with it disconnected. i am thinking the coil is bad, right? if the other ignition compnents were bad it would effect either two cylinders, or all, correct?


this is after the engine running great last night, although it did seem a little weaker getting onto plane than usual, and a little less speed at W0T, but i just assumed it had to do with my father sitting very far aft, and nobody foward. coil?

[jb123]

if the coil will jump a quarter inch it should be fine.if you pull the wire and no sound change it still may not be getting the fuel it wants also.

[Ken]

T-T,
Try swapping the suspect coil with another to see if the symptom follows it - if so, then the coil or spark plug wire is bad. If not, then bad spark plug, or not enough fuel getting to that cylinder .
Don't know about your old filter, but don't think it was 10 microns.
Also, if your spark plugs are at least one year old, I would put in new ones.
Ken K

[ July 02, 2006, 08:47 PM: Message edited by: Ken ]

[Tractor-Tug]

are the wires themselves replacable, or just the coils as a unit?


also, i dont know what you mean by jump a quater inch, as in the arc? how would i see that through the spark plug boot?


hopefully it is getting enough fuel, i'm sick of this fuel system. hopefully it isnt since there is a decent amount of unburnt (partially&gt fuel comming out of the exhaust. if it helps, at idle i just get some drops of fuel working up to the surface. if i rev it some, i get bigger slicks of fuel, some seem kind of white-brownish in color and foamy. i would think partially burnt?

will try swapping coils to another cylinder and seeing what happens. hopefully this is an easy fix for once, i think i'm due for one.

[Ken]

T-T,
Un-burned fuel coming out the exhaust can be from two problems. One would be a cylinder(s) not firing, and the other would be a ruptured diaphram in the fuel pump.
If your fuel pump is at least five years old, I would replace it ($32 at boats.net). Or tear it down and inspect/replace the diaphrams.
Good luck, and let us know how you come out [img]smile.gif[/img] ,
Ken K