Sudden Bog at WOT

[paulgp6022]

Hi, I was coming in today and my year 2000 40 hp 3 cylinder Mercury outboard started bogging. I had to let off the throttle to let the motor stay running. It would only go at 1/4 throttle or so. If I gave it WOT it would bog down. I started to push in on the ignition key which actuates the choke or primes it, I don't know which one,and this allowed WOT to work, but only as I kept pushing in on the key and letting it out. Finally it seemed to clear out and run as expected. Can my fuel filter that is original from 2000 be the culprit? I changed it when I got home and the motor seems to respond better to the throttle. I am going to put a water separator on it tomorrow to just to be safe. Thanks for any info.

 

[paulgp6022]

Re: Sudden Bog at WOT

ttt

 

[paulgp6022]

Re: Sudden Bog at WOT

Anyone?

 

[dstuard]

Re: Sudden Bog at WOT

Fuel restriction of some sort. Could be in the fuel line or could be the fuel pump. The experts on here are going to tell you to get a manual.

 

[jim dozier]

Re: Sudden Bog at WOT

Sounds like you had a piece of floating crud (as opposed to gum deposit) that blocked the the high speed jet on one carb causing it to drop 1 cylinder due to lean condition. Backing off throttle returned bad carb to idle circuit which wasn't blocked. Later the crud moved off of the jet. The good news is that it moved the bad news is where'd it go and running lean is not good for the engine. At the very least I would drain the carb bowls if they are easily accesible. If it does it again don't continue trying to run it at speed, go home and rebuild the carbs. Good idea to change the filters.

 

[paulgp6022]

Re: Sudden Bog at WOT

Thanks for the reply. I changed the fuel filter at the motor, and today I added a Tempo water seperator/fuel filter kit at the tank.<br /><br />When I checked the plugs, all three looked a little on the white side(lean). Could this mean that the main fuel line itself was clogged which limited fuel to all three carbs? I hope I didn't do any damage! It runs nice now on the muffs. I am going to try it tomorrow.

 

[jim dozier]

Re: Sudden Bog at WOT

Check your tank venting system also to make sure it is venting. Your description of the plugs does sound like it was running lean. When you take it out again, I would take it for a short spin only and pull the plugs again and give them another look. Hopefully it was just clogged filters.

 

[paulgp6022]

Re: Sudden Bog at WOT

Thanks, I did open the gas cap while this was bogging, and that didn't help, which would lead me to believe that the vent is working properly. What color plug on that motor is acceptable? Like a tan or chocolate brown color? Another question is with two filters now in the fuel system, will this starve the motor for fuel because of all the filter elements the gasoline has to pass through? Thanks again!