2001 mercury xr6 only getting to 4000 rpms

[bamamccoy]

Need some help.I have a 2001 mercury xr6 on a 18 foot triton. The boat runs and idles great in the mornings, but after about a half day of fishing the boat will only reach 4000 rpms and not get on plane. It’s done this the last two times I’ve taken it out. Fuel pump, carb, fuel lines etc.... have all been checked and look good. Figuring it’s got to be electrical.

 

[Teamster]

I had one act like that,...

Turned out when one of the cdi boxes got hot it lost rpms,..

I replaced both and it's been fine since,...

Something to check,...

 

[Faztbullet]

Its dropping a couple of cylinders. Next time out and it fails, pull cowl and hook up a timing light and see when are not firing

 

[bamamccoy]

Thanks for the input. I'll try both next time I put it on the water. Everyone I've talked to have come up empty. Hopefully one of these suggestions will fix my problem.

 

[bwguardian]

Pull the plugs and take a look...they will tell you which cylinder and/or cylinders are acting up.

 

[QBhoy]

Sounds like compression test time ? Best case manually choke the carbs with your hand and listen. Should give you an indication if it’s fuel or carb related.

 

[Dukedog]

Its dropping a couple of cylinders.

check cdm's and ecm…..