honeymoon over...MFS6D

[Dotard69]

well the honeymoon is over after 5 hours...



backdrop: brand new SailPro, 5 hours of break in. only using ethanol free fuel. always run motor til carb empties. had run fine thru hour 3, then stalled 4x entering slip when a low idle. idle speed was low so fixed that and all seemed fine...



went out yesterday. started and ran fine for 30 minutes, then set sail for about 20 minutes before wind died. started motor.

started ok, right away it was hunting wildly for 30 seconds before stalling. restarted after 4 pulls, some minor hunting at mid/low rpm. then seemed to settle down. seemed to run ok at low idle, then decided to enter the marina....



ran fine at mid/high rpm. maybe occasional situation where it slightly dropped rpm.



as i entered fairway and lowered rpm to about 2000 or so, it started hunting, not as bad as before but i was playing the throttle, pumping bulb to keep it going but pumping bulb didn't seem to impact anything.





made it to slip... next day..



1) checked oil level. between hash marks no issue

2) no apparent air leaks in fuel line. bulb is hard when i pump it and motor is off (also tank cap is open...)

3) noticed that at initial start fuel filter gas is kinda low at idle, too a while throttling up to get her to fill up.

4) pulled plug. see pix. is this normal after 5 hour break in? plug was this way after prior days run. it was dry, but carbony as you can see.





also, using the Tohatsu



also, using the Tohatsu OEM fuel line, kinda small diameter. i replaced the fitting to tank, using other tank i had as its the only tank that fits. i cleaned it and the screen isn't blocked. and there is no apparent air leak.



any ideas other than pulling card, 4 hour soak, etc, etc...

 

[MattFL]

Fuel and electrical problems can sometimes behave similar. But the low hanging fruit is probably to take the carburetor apart and see what you find. I had a problem once where a tiny piece of rubber from a disintegrating fuel line got lodged in the float needle and the carburetor wouldn't fill with fuel. Your gas lines are new, but maybe you've got something as simple as some junk clogging things up. The easiest way to check without disassembly is as soon as the problem reproduces open the drain on the float bowl and see how much fuel comes out, try to judge if it's a bowl full.

 

[racerone]

Brand new ??----Is there not a warranty ?-----Hurry to your dealer I say.

 

[Dotard69]

Brand new ??----Is there not a warranty ?-----Hurry to your dealer I say.

oh for sure 5 year warranty, it’s a pain to remove it off boat at slip…carry to car…etc. I’m gonna stop by the dealer this week with “plug In hand”. Luckily I still have my 1994 5hp 2 stroke! Loud as hell and not best running, but reliable as ever…

 

[km1125]

I agree with Matt's suggestions. Plug doesn't look like too much of an issue. A little more dark than what I'd like, but not enough to be a "bad" issue.

You probably don't have to do a long soak. Seems like your is more of a "floating dirt" issue that probably could come clean by just spraying out all the orifices and the bowl.

 

[Dotard69]

Update. Dealer told me it was running too rich. They made an adjustment and it appears ok, at least testing throttle and idle shifting at dock. Acid test will be heading out for an hour or so, then back to slip. I will say I’ve got my olde 2 stroke so well tuned it purrs under idle, and shifts like a dream. But hate the noise….

 

[Dotard69]

Update 2: got it back from dealer, adjusted low speed pilot screw. Idle was set a little high at 1400 rpm as read on my TinyTach. everything seemed fine going out. Coming back in it stalled once while at idle. WTF #1… Took it out again today, started from cold perfectly, ran and idled great. When heading back I noticed slight, occasional hunt under 2200 rpm. When I dropped her to idle it would not idle lower than 1850 rpm… WTF #2. But didn’t stall when shifting f/r. At dock I adjusted the idle down. this motor is becoming a $2K POS….

 

[MattFL]

My two thoughts (1) Replace the spark plug. I've had failing spark plugs act like it's overly lean before. You just get a weak spark and a bad burn so the motor acts lean. Try this first only because it's super easy. (2) It's more likely you've got some junk in or around the pilot jet. Has anyone taken the carburetor apart yet and really gone through the tiny holes? Soak in an ultrasonic cleaner if you have one, but for sure blow out every hole and orifice with cleaner AND compressed air. That model motor has a reputation for being durable and reliable so you've just got a small issue to track down.

 

[km1125]

I agree on replacing the plug. They can cause some weird issues, even a new one. That's why I always replace a plug on a GOOD running engine and keep IT as the spare, rather than just buy a new one for a spare.

 

[Dotard69]

Guys thx for input. I put a new plug in just before i initially brought it to dealer, an NGK. But maybe I’ll get another one and put it in for ha ha’s.

The dealer adjusted the pilot screw and one hoped at a minimum he sprayed it clean. At this stage i‘m going to wait ‘til haul out then bring it over for service. It’s a hassle taking the motor off and dragging my olde, yet ever reliable 2 stroke Tohatsu… the 2 stoke I personally serviced over 9 years, never failed me.

 

[pvanv]

How did they adjust the pilot screw when it has an EPA plug blocking access? It's a violation of federal law to take that out. If you can't idle down low enough, that really sounds like some varnishing in the low speed circuit. Do you run the carb dry at the end of each day, unless you are running again tomorrow?