90 Merc no WOT!!!

[Chaney101]

hey guys I was running at the chesapeake today. When I opened up the throttle in forward, the motor would not pass 4000 RPM. Neutral opens up fine as does reverse. I checked spark when I got home with a timing gun and changed plugs on the water. It takes forever to even get to 4000? Any help would be appreciated. 2003 ELPTO 90 HP 2 Stroke only under load does it do it because when I trim way up it will rev up.

 

[Jugfisher]

Re: 90 Merc no WOT!!!

When is the last time you rebuilt carbs.

 

[Chaney101]

Re: 90 Merc no WOT!!!

I never have. is this a tough job?

 

[Silvertip]

Re: 90 Merc no WOT!!!

Not if you have a service manual. These are pretty simple carbs and nothing springs out at you during the disassembly process so pay attention to detail and its a simple job. Two tips: 1) Before disassembly, turn the idle mixture screw in while counting the number of turns until the screw is lightly seated. When you reassemble the carb, lightly seat the screw and then back it out the number of turns you noted prior to disassembly. 2) With the float and inlet needle installed, before further assembly, tip the carb upside down and blow into the fuel inlet. If air passes, you did something wrong. If not, the inlet needle is seating properly and you can continue with assembly. Remember, the carb needs to be totally disassembled, and every passage made squeaky clean.

 

[Chaney101]

Re: 90 Merc no WOT!!!

Thanks Silver, My seloc is on the way !

 

[achris]

Re: 90 Merc no WOT!!!

Before you go pulling things like carbs apart, check some of the usual suspects. Check compression, maybe throw in some new spark plugs. Had a real hard one to track down a few months ago. Similar fault. the problem was the spark advance lever pivot bolt had a bit of corrosion on it and was stopping the spark from advancing correctly.. Check the arms are free to move. Pull the bolt (carefully) and clean and grease it...

Chris.............

 

[rustyscrew]

Re: 90 Merc no WOT!!!

Has it run well for you before? Just wondering if you might have the wrong prop. Is this a new engine for the boat?

 

[Chaney101]

Re: 90 Merc no WOT!!!

no same prop, it ran fine the week before. i took it out and bam. It would sparactically jump in rpm, after a while it stopped doing that as well. It would just take forever to get to even 4000 rpm. It winds up fine in neutral.

 

[Chris Cole]

Re: 90 Merc no WOT!!!

Your problem sounds eerily similar to the problem Iam having with my 40hp merc. When I am neutral I can wind it up to 5000 all 3 cylinders, but with load; WOT only about 3500 RPM's 2 cylinder's working. I think I could have a bad or open reed.

 

[JUSTINTIME]

Re: 90 Merc no WOT!!!

Your problem sounds eerily similar to the problem Iam having with my 40hp merc. When I am neutral I can wind it up to 5000 all 3 cylinders, but with load; WOT only about 3500 RPM's 2 cylinder's working. I think I could have a bad or open reed.

reeds would spit fuel out the carb