Force 75 running rich, poor idle, lack of rpms

[Jeffromxer]

I have a 97 Force 75ELPT on a 20 foot pontoon I just bought. It ran good when I got it. However max RPMs were only 4500. The prop was chewed up so I replaced it and viola 5200 and running well. Not for long though. Next time out I throttled it up. It ran good to 5200 RPM for a few seconds and then dropped to 4500. Ever since then It will not idle and will not reach maximum RPM. I pulled the cover to see what was going on and fuel was pouring out of the throat of the carb. I pulled the carb and cleaned it and made sure the float was adjusted and needle was seating. I believe it is. I can pump the ball and it gets hard and holds pressure. I also noticed black debris in the fuel filter so I replaced it along with the hose from the tank to the primer line. I still have very low idle and stalling and lack of RPMs that I believe is due to running rich. However it runs great from 1000 to 4500 RPM. Here is the weird part. If I pull the fuel line from the carb bowl to the Fuel Enrichment Valve I can get 5200 RPM and smooth running but still no idle. Does this engine open the FEV at WOT? Any ideas would be greatly appreciated. Thanks

 

[jerryjerry05]

Sounds like the diaphragm in the enricher has gone bad??
It goes bad and feeds extra fuel into the carb.
The idle: could be the enricher,or the air screw? what's it set at?
Start at 1 and 1/8th turn out. After you fix the enricher.

 

[Jeffromxer]

The idle mixture screw is currently at 1 turn out but I have tried almost all adjustments with no luck. I have also replaced the FEV with a known good one from another motor also with no results. Thank you for the ideas. I just cant think of why taking fuel away from the enrichment valve would lean it out at WOT? Forgot to mention I have also rebuilt the fuel pump and done spark plugs and wires.

 

[Jeffromxer]

Well, out of other ideas I decided to remove the reeds and inspect them. I found the 1 petal completely missing for the #1 cylinder. Looks like I am buying a set of reeds. I found some boyesen reeds on amazon. Does anyone know if they come as a set for all 3 cylinders? Amazon's descriptions leave a lot to be desired in most cases.

 

[pnwboat]

Usually the replacement reeds come as a complete set to do the whole motor. At least that's the way the Boyesen and Chris Carson Marine reeds come.

 

[Jeffromxer]

Thanks for the input pnwboat. I have the reeds on order. I will update the post when I get them installed.

 

[Jeffromxer]

I got the reeds installed and all is well. Idles perfectly and runs great. I never did find the broken petal from the reeds. I spent considerable time looking and am fairly sure it passed through the exhaust. I believe the reason that removing the fuel line from the FEV helped is that just having the hose at the bottom of the carb open to air caused a loss of vacuum on the fuel in the bowl. Thus decreasing the amount of fuel the carb could supply. Thanks to everyone for their insight.