1991 9.9hp Performance Question

I took my Weldbilt 1652 Jon Boat out last Saturday and was questionable about it's performance. Prior to Saturday, I had not ran the motor since Sept 2008. I ran all the gas out of the carb before putting it up. In the past, I was able to get my boat to go 19mph with 2 adults and on Saturday I was only able to get about 13mph with the wind at my back. When I was priming the motor I noticed brown colored fuel, so I drained it off until I got to the fresh fuel. I beileve some of that brown fuel got into the carbs. I assume that it was the gas left in the fuel line. After the fresh gas got to the motor it started on the 3rd pull and it idled fine. When I put it in gear I felt that it could not achieve WOT. I have since added some seafoam to my gas in hopes that next time I run it it would improve the performance by cleaning the carb. Is there anything else I should do that does not require me to disassemble the carb. Also it is time for a new water pump and a lower unit oil change, will this hinder performance also? Thanks in advance for your responses, I love this site.

Re: 1991 9.9hp Performance Question

Running the carbs dry isnt removing all the fuel from the bowls,Not to mention it isnt that great for the motor.It will run lean as the bowls run out of fuel.Fuel will varnish and leave funk that was probley picked up and stuck in the high speed circut in the carb.Seafoam may help but it may need to be pulled and cleaned.My 2 cents

Re: 1991 9.9hp Performance Question

if the main and idle circuits are varnished up and most likly they are, by the time the seafoam cleans the jets you most likly will have detonated a piston.
clean the carb before running again to insure all is well with it.
and yes, contrary to popular belief you CANNOT run the carb dry.
most carbs do have a drain on them though.

Re: 1991 9.9hp Performance Question

You may be losing one cylinder.
Pull the plugs see if one looks wet.Swap plugs and see if plug gets wet in the same hole.Probably not the problem but won't hurt to have a look.

Re: 1991 9.9hp Performance Question

I thought I was running my carb dry on my 25hp yamaha and they are right. When I pulled the carbs the top one was very clean still but the bottom one had gunk/varnish built up in the bowl and around the tip of the high speed jet. Was pretty easily cleaned and reassembled, did not need gaskets. If I hadn't broke the Air adjusting screw off at the end of the job the whole process would have only taken me a couple of hours.