tuning up my force (merc&late owners of Force)

Has anyone done this before my motor only runs 3500rpm all out? Could my throttle linking need to be adj at the shifter?

Re: tuning up my force (merc&late owners of Force)

NOT AN EXPERT,BUT ANOTHER REASON COULD BE THE PROP PITCH. BEST OF LUCK<br />DONZEED

Re: tuning up my force (merc&late owners of Force)

Take the cowling off, and put the throttle lever at Wide open. Then look at the butterfly's on you carbs to see if they are completely open. If this isn't the case, give us as much info as you can about how it is acting, what the plugs look like, anything you have done to it lately, etc. Maybe then we can help from there. Good Luck

Re: tuning up my force (merc&late owners of Force)

Are you runnig on all cylinders?

Re: tuning up my force (merc&late owners of Force)

Just took a look at wide open throttle the carb butterfly valve is barely opening like not even half way. This could be why the engine does not have that 2cycle growl. Where both parts come together so that it opens the mark is lined up with the screw. What next to adjust it the cam does not seem to allow the butterfly valve to open. Could the carb on the inside lost a pin or something.

Re: tuning up my force (merc&late owners of Force)

If the cam and timing arm are moving, make sure all the screws on the linkage that connects the carbs are tight; particularly the one the cam makes contact with. They should have a screw for each carb so you can put them in sync. Tell us what you come up with.

Re: tuning up my force (merc&late owners of Force)

All valid areas to look.<br />Not much to add without knowing HP.<br />Except, do you trust your tach?

Re: tuning up my force (merc&late owners of Force)

Sorry I was wrong about the carb valve not opening. If I put the boat in foward then open her up yes the butterfly opens all the way. The 96 force 75hp stalled and was very hard to start again. I belive the jets in the motor are for AZ alltitude. I live in the mountains in Utah at 6700ft? Would this make much a difference. I am going start a new post how to clean and change the jets in the carb. Thanks

Re: tuning up my force (merc&late owners of Force)

I don't believe the jetting would have that much effect on the engine to restrict it to 3500 rpm's. What is the history of the motor? What prop are you running (being severly over propped for the boat can also effect the running)? It could also be possible that your timing is not advancing (which is bad).<br /><br />I doubt any "late" mercury owners can help but possibly owners of late model mercury motors can. <br /><br />Good luck. Bob

Re: tuning up my force (merc&late owners of Force)

My prop is a 17pitch its the smaller size prop also. Not like my old 89(80hp) merc.

Re: tuning up my force (merc&late owners of Force)

Hello everyone,<br /><br /> I am new to the forum. I have a 1991 - 90 HP 3 cyl Force. It will run at 4350 RPM and then all of a sudden it will acft like some one cut the throttle to half position and only run at 3500 RPM. If I change the plugs it will run OK for an undetermined length of time and - you guessed it back to no power and fowled plugs. I have been reading my FORCE outboard repair manual (which is extremely hard to follow) and it keeps refferring to a cracked reed. I finally found something in the manual about the engine not recirculating at slow speeds and then when you go full throttle it will dump the gathered fuel and fowl the plugs. I am trying to find a place to buy parts so that I can replace the reeds in the recirculating mechanism. When it cuts its own power I have taken the top off and check the throttle position while under power (very dangerous maneuver) and found that it is at full throttle (just not full power).

Re: tuning up my force (merc&late owners of Force)

If you are at 6700' ASL then the jets should be smaller by .002" per 2500'. In your case from .072" down to.0068" or less. Even with the right jets don't expect max rpm at that altitude. You may only get 4500 rpm with the smallest prop.