PLEASE HELP with 4.5 Mercury bog!

[paulgp6022]

Serial number 4759549 year is 1979 I think. 4.5hp Mercury single cylinder. It has been in the family since new. It recently developed a bog at WOT and dies. But if you let off the throttle it comes back to idle fine. It has been sitting for 5 years or so. Could it be the high speed jet? I cleaned the carb out, but it is still there. What should I do? Can someone also tell me how to remove the front mounted choke? Thanks

 

[The Marine Doctor]

Re: PLEASE HELP with 4.5 Mercury bog!

Nice rig...we sell those.<br /><br />Sounds like the fuel supply is being limited...Most likely by the highspeed jet. As with small engines...if the gravity feed or fuel pump is bad...you will still get full throttle..until you run out of gas.<br /><br />TMD

 

[paulgp6022]

Re: PLEASE HELP with 4.5 Mercury bog!

Thanks I like the Fisher too. Rides like a bigger boat for some reason, but I'm not complaining!<br /><br />The fuel pump on the 4.5 was replaced last year as a precaution, but it still bogs.

 

[Fouled Plug]

Re: PLEASE HELP with 4.5 Mercury bog!

Did you clean the carb by dunking it and blowing out with air? And did the bog appear right after the fuel pump replacement, or before?

 

[paulgp6022]

Re: PLEASE HELP with 4.5 Mercury bog!

The bog was there before and after the fuel pump replacement.<br /><br />I couldn't get the carb off because of that dam choke knob. Does anyone know how to remove the choke so I can get the carb off? I was able to only get the float out and clean the idle jet that screws out from the top. I really need to get that chole knob off. Thanks for any info.