[Hoochee]

Just bought the boat. 2000 4 stroke 90HP outboard. Runs well, and comp checks out. All plugs indicate a good fuel burn and are even.
It sat in an indoor garage since Oct. Fresh fuel, and a good long haul down the lake today. It runs smooth once on the plain and blasted along without a hitch. The mis is not consistent and only appears when you are going from slow speed to plain. Not always the same RPM and not every time. I see what looks like an air filter on it, could it be starving for air..It has a fuel filter inline inside the cowel. It looks clean. I don't know when the last tune-up was done.
Any suggestion on where to start. Carb clean... plug wires.. I'm not overly mechanically inclined beyond the basics of plugs etc.

Thanks for the advice,
Hoochee

 

[reelangler]

Have you checked the spark plugs? One may be cracked or something.

 

[Hoochee]

I checked them, but didn't look for cracks...I only looked at the electrodes on the heads. I will pull them back out and double check. Maybe a plug wire has a prob..
Hoochee

 

[reelangler]

Be sure not to crack them on their way back in too :wallbash: I don't know form experience, but i've heard it's really easy.

 

[professori]

I don't know when the last tune-up was done.
Any suggestion on where to start. Carb clean... plug wires.. I'm not overly mechanically inclined beyond the basics of plugs etc.

Thanks for the advice,
Hoochee

If you don't know when it was last tuned and you are not confident you can do a good tune-up, I'd suggest you take it in and get a proper tune up done now before the season really picks up.

 

[bigjay]

I don't know it the 2 stroke and 4 are similar enough for compairing my problem to our... but I don't think any harm can be done with my suggestion. I after every winter I have the problems of the bottom spark plug getting fouled with hydrocarbon goo and it mis fires or does not fire at all. I just change the plug. Another problem I had when the engine was new was that the gap on the plug got messed because of overcomprestion - that what the mechanic said, and I'm sticking to it - after re-gapping and cleaning the electrods it worked fine.
If you got another set of plugs hand try throwning them in see if it works.
have fun, Jason

 

[marko]

Try running a bottle of carbcleaning in the fuel and re-check the plugs. Also nothing wrong with
replacing the filters.

:beerchug: Marko

 

[bigjay]

I agree with marko.
Have fun, Jason

 

[Hoochee]

Thanks for the tips. I am going to change the plugs, try a bit of in gas carb cleaner, and change the filter. Funny thing about the filter. I used the boat Friday, came home from work on Sat afternoon and found the motor dripping gas from the lower leg. I opened the cowling and found gas dripping at a good rate from the plastic in line fuel filter. The seam of the filter (two pieces molded together) was not air tight. The temperature rise on Sat caused the fuel tank to pressurize the line and bring the flaw to light.
I read that these big 4 strokes suck huge air when they are run up, and can run lean causing a mis or hesitation. If I was sucking air into the fuel system through the filter I suppose it wouldn't help much. We will see next time out..

 

[Fishaholic]

If the filter is leaking there is a good change that you are sucking in air while running cause a off fuel/air mix, that would make it miss

 

[Hoochee]

The update.... I changed all the plugs for new, put in a new fuel filter, added some carb cleaner additive to the gas, and ran it for about 10 minutes with the ear muffs on in the driveway. I let it sit for a week, then had the chance to take it out on the Pitt River today for a quick outing. Started first turn, idled well, and no more hesitation during heavy throttle up. I think I got it :thumbup:
Thanks for the tips..