115 yamaha inshore - sputter/oil leaking

[spete]

I have two problems that may be related/just started on my '98 115 yamaha 'inshore model' ... I've noticed that the motor will run rough at idle after it's had a trip across the bay (30 minutes or so of running) Last three trips the engine has also started to sputter a little while waiting at the ramp to take out - then on the last trip it actually sounded like it was missing one or two cylinders and completely died while idling after running out to a fishing spot (20-25 min). Will run great at full throttle and anything above a low idle. Now I've also noticed black oil leaking from beneath cowling down the upper shaft. So far I changed the plugs (all basically looked the same blackish and a little wet), checked for loose wires, replaced the fuel filter, ran Ring Free/decarb (which I do about every 10th tank) - not sure what's going on? Based on what I've read on the message board - I can't figure out if the oil leak is coming from some sort of blown out seal that causes the sputter at low rmp or that the miss firing at low idle is creating unburnt fuel/oil to be blown out somewhere it shouldn't be? Any help on this is greatly appreciated.

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

Spete , I would eliminate the easier possibilities first by suspecting restriction or gummy deposits in carb idle circuit and orifices.Also insure that you have good spark to all cylinders at cranking speed.Plug leads should jump 1/2 blue spark to ground.A compression test would also be advisable to eliminate low compression as culprit.Without a visual I can only guess that oily residue running down engine leg could be leaking crankcase seal(which could cause symptom)or exhaust cover leak.Are you using the factory specified plugs?

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

I'm using factory specified plugs and did a compression test about a year ago and all cylinders were 140-135. How would I go about cleaning the gummy deposits in carb idle circuit orifices? Also, for the spark plug test do I start the motor and then pull one plug wire off at a time and ground to block for arc?<br /><br />Do you think it's a little suspect that the oil dripping problem is occuring roughly the same time I started having the rough idle?<br /><br />Is the exhaust cover leak something I can just retorque or replace a gasket?<br /><br />Thanks for all your information!

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

spete , best to remove carbs one at a time for inspection and cleaning.If you are not familiar with this procedure a manual is real handy.<br />Spark test can be conducted with motor not running and leads disconnected.Check at cranking speed one at a time with the other leads grounded .<br />You can inspect exhaust cover for potential leaks with motor running and cowl removed.Be careful around rotating components.Check cover bolts for looseness and visually inspect perimeter of cover for signs of leakage.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

Sorry, I meant to ask you about the crankcase seal also. Is that something I can get a partial external visual on and inspect for leakage? And do I replace a gasket on the exhaust cover or retorque? <br /><br />With the spark plug test do I remove all four wires and ground three and then test for the arc one at a time/how do I ground the other three? <br /><br />I will definitely need to get a manual and read - i have a basic understanding of outboards but probably need to give myself a crash course in all the systems/workings.<br /><br />Thanks OB for your replies

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

spete ,I use aligator clip leads for grounding.Not good on the ignition system to leave open while cranking.<br />Some exhaust covers have gaskets and some do not.<br />As far as the crankcase seal,this is worse case scenario and will require removal of powerhead to service.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

ob, thanks again for all the info - will help me greatly with the trouble shooting.<br /><br />I don't mean to be dense about the whole spark plug test but do I take ...<br /><br />double ended aligator clips and clip one end to each of the removed spark plug leads <br /><br />use the other ends of the aligator clips to connect three of them to the motor metal somewhere/ground and then hold the fourth one I'm testing near the plug and look for the arc?<br /><br />Thanks!

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

p.s. - the sun is breaking through here in Spicewood - why aren't you out fishing? Big reds swimmin' around on those flats right now looking for a bite to eat!!!

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

That's how I do it.You can arc them to any location that has bare metal ,including sparkplug end.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

... sounds like I'll need a buddy or really long arms to conduct the spark plug test!!!

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

You can use a remote starter button.One lead goes on the large cable to solenoid and the other to the ignition wire on solenoid.Some guys use something as simple as a household switch .

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

ob, you need to change your initials to os ... old salt. <br /><br />* Hey, if you ever get a really strong north wind or any direction gale for that matter there's a good place to hunker down with some bait down the Island Moorings channel - down about a mile on the right - gut comes through right where the channel makes a left. Caught plenty of reds, trout and flounder in there.<br /><br />muchas gracias!

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

10-4.The wife calls me OF.Go figure.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

Hey ob, took off the lower cowling covers (bolted on sections) and it looks like the oil is dripping from very near the exposed impeller shaft (I'm guessing that's what the spinning shaft I see is between the power head and the lower portion of the motor). I would suspect that there are two seals top and bottom and maybe one is leaking? is this a critical leak and should i have it fixed immediately? Your thoughts on this would be appreciated.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

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[ob]

Re: 115 yamaha inshore - sputter/oil leaking

Spete,First thing is to make absolutely sure that this oil accumulation is not sourcing from the lower carb and running down to lower crankcase seal area.If it is the lower crankcase seal,first thing I would do is eliminate the possibility of your sputtering problem being fouled carburetors.The leaking seal may or may not be something you can live with depending on the severity.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

If this is the crankcase seal, sounds like I may need to take it to a shop ... any idea what a reputable shop will charge to do the job?

 

[ob]

Re: 115 yamaha inshore - sputter/oil leaking

spete,depending on the shop and hourly charges I'm guessing between $40-$50 per hour labor.Reputable shop should be able to give you a quote.I'm thinking the lower seal is no more than an "o"ring and retainer plate.Don't know the specifics on yammys design.

 

[spete]

Re: 115 yamaha inshore - sputter/oil leaking

Thanks OB, it sounds like it may be a rather simple procedure but on the other hand I seem to get the full dose of Murphy's law going everytime I attempt a job myself (frozen bolts, special tool required, wrong part/multiple trips to the parts place, etc.) I figured if it was a matter of tightening some bolts or replacing some easy to get at seal or gasket I might be able to swing it. I'd hate to mess up a motor that's been running great all things considered. I appreciate your advice.