Engine "sneeze"

[giffman]

I've noticed recently my 02 Yami 150 OX66 will "sneeze" slightly when slow trolling just off idle. When in neutral or on plane it does not seem to exhibit this condition other than an occasional sneeze/stall on cold start. The sneeze on cold start is much more pronounced than the one I hear when slow trolling.<br /><br />I've read that this is an indication of an intermittent lean condition?...but all the posts talk about carb'd motors? The sneeze is not real bad but you can definately hear it.<br /><br />I want to jump on this potential issue real quick...especially since the boat shop is slow right now!!<br /><br />Thanks, <br /><br />giffman

 

[rodbolt]

Re: Engine "sneeze"

how much correct routine maint has the motor had?

 

[giffman]

Re: Engine "sneeze"

All the maintenance that the owners manual calls for and then some. I've replaced fuel filters every year (approx every 40 hrs), changed plugs at 80 and at approx 130 hrs, lower unit oil changed every 40 hrs, impellor replaced at 100 hrs, plus the recommended 10 hr and 100 hr maintenance at the shop. Not completely sure what those all involve. I use ring free probably 70% of the time.

 

[giffman]

Re: Engine "sneeze"

bump

 

[giffman]

Re: Engine "sneeze"

bump bump

 

[andy6374]

Re: Engine "sneeze"

Sounds like you are doing a good job on the upkeep of the engine. A sneeze is typically associated with a lean condition. The "sneeze" you talk about at idle speeds can be caused by the throttle shutters in the carb throats not being fully closed at idle, hence decreasing the fuel/air mixture. It is possible that the screw that attaches the throttle linkage to the arm on the carb that opens and closes the throttle shutters is loose. Check it and make sure they are all closed at idle.<br /><br />Have you ever had the carbs cleaned? It's easy. This would be part of the maintenance routine. Try to figure out what went into your 100hr maintenance at the shop.

 

[rodbolt]

Re: Engine "sneeze"

when was the last service,100 or 200 or whichever one is due that was performed according to the checklist ?

 

[rodbolt]

Re: Engine "sneeze"

andy<br /> ox66 is EFI, not only that it has an O2 sensor to help adjust fuel delivery at all RPM and engine temps. however it has 6 shutters and if one has slipped or moved it will create the above problems, but if the 100 and 200 hour services are being done at the correct 100 hour OR 6 month and 200 hour OR annually its never an issue.

 

[giffman]

Re: Engine "sneeze"

It has been approx 15 months (?) since the "100" hour maintenance was done. So I guess I'm due for the 200 hr service...which may cure this issue. <br /><br />Rodbolt - you mention the O2 sensor...I posted a few months back about a loud ticking noise and as you surmized it was indeed the o2 sensor draw tube being stuck that caused it. Since it was cleaned the engine has not made that noise. Since the last issue I had and now possibly this issue was O2 related I'm seeing a trend. Clean the O2 annually huh ?!!<br /><br />giffman

 

[rodbolt]

Re: Engine "sneeze"

some engines, depending on use, have to have the O2 sensor cleaned and tested every 75 hours,<br /> the flame test is NOT reliable I dont care if it is in the manual. if you wish to do it yourself buy the test harness and a 25 dollar radio shack digital multimeter. while your buying buy the TPS harness as well.<br /> some dealers will do 100 hr sevices for years. 2 100 hr services do NOT equal one 200 hour service. some of the guys that troll for 4-6 hours for tuna need a readjusted maint schedule.<br /> that motor also has recirc check valves that must be tested periodically. dont bother hunting in you manual odds are there is no mention of it. does not negate the fact they are there and require periodic testing and replacement. so it depends on if the service center goes strictly by the service chart or if the wing it.<br /> the marine tech guide for the last couple years has some good technical info as well as the service schedule.

 

[Scaleman]

Re: Engine "sneeze"

Having the exact same problem! Te search feature works.