engine problem

[Alaska Gray]

Ok, this weekend I was in Homer returing to the dock, when one of my 115 started to act funny. It would now go past 27 rpm and then started to sputter/mis fire. I turned it off then back on and manage to get it up to 42 rpm but it still mis fired at 42rpm. I'm thinking it might be a spark plug. but at the same time when I put it in nutral the engine would shut off. This engine has 48 hours on it. Would a spark plug go bad this soon? It's a bran new boat and engine? If it's not the plug what else could it be?

 

[kgrant]

What model of engine?

 

[AKmud]

Check the wires?

Check the wires?

My 40 did that to me on the river a couple of years ago. Come to find out, when I had been servicing it, I had not gotten one of the spark plug wires snapped all the way on. It would run rough at idle and would only get to about 1/2 throttle RPM when WOT. Pushed the cap all the way onto the plug and she ran like a champ. Check the easy stuff first.

 

[Alaska Gray]

What model of engine?

Yahmaha 115

 

[Alaska Gray]

My 40 did that to me on the river a couple of years ago. Come to find out, when I had been servicing it, I had not gotten one of the spark plug wires snapped all the way on. It would run rough at idle and would only get to about 1/2 throttle RPM when WOT. Pushed the cap all the way onto the plug and she ran like a champ. Check the easy stuff first.

I'm hoping it's nothing more then a bad plug. But why would it go bad so quick?

 

[AKmud]

Who knows....

Who knows....

Something may have made the porcelain crack or a speck of metal is grounding the plug out. Did you notice if the engine started vibrating really bad when it was running rough? If so, it helps diagnose that one cylinder is acting up. Another test is to run it with the cover off and pull one spark plug wire off at a time(hook it back up before you pull another one). Each time you pull a wire the engine should run differently. If you pull one off and the idle doesn't change, thats your culprit cylinder.

Good luck!

(Don't forget to wear a good pair of gloves!)

 

[Akres]

I would check the fuel filter very closely. Replace it if in doubt. My guess is you got a little water or some sort of restriction. Being a new boat, it is not uncommon to find metal shavings from the threads that were cut in the new tanks. Also blow out the fuel lines and make sure there is no teflon thread tape in them.

 

[Alaska Gray]

Thanks. I'm taking it to Dewey's any for other add on's so they will take a peek at it.

 

[AKmud]

twins

twins

I would check the fuel filter very closely. Replace it if in doubt. My guess is you got a little water or some sort of restriction. Being a new boat, it is not uncommon to find metal shavings from the threads that were cut in the new tanks. Also blow out the fuel lines and make sure there is no teflon thread tape in them.

He's running twins though and only has a problem with one. I would think a fuel problem would effect both engines.

 

[kgrant]

OK, 2 stroke/4 stroke?

Not uncommon for plugs in a 2 stroke to foul up after running the breakin mixture through it. I know you're a little past that though.

Have you checked your plugs, how are they burning?

 

[Alaska Gray]

Twin 4 stroke yahama's.

No I have not checked them. I did not have a long enough shocket to reach them

 

[Alaska Gray]

How can I tell if the fuel filter is bad?

 

[Alaska Gray]

Took it to Deweys' this morning and it's not noon yet and it's fixed. Great service. The problem was a wire that shorted out.

 

[kgrant]

Do you know which one it was? Just so others can keep an eye on it.

 

[Alaska Gray]

Do you know which one it was? Just so others can keep an eye on it.

I will let you know when I go pick it up here in a hour or so.