Fuel filters

[merc850]

I had a fuel problem on my recently purchased Merc 850 (1975), this has back draft carbs but they have a different top than the ones pictured in the manual. I went for a ride and the bottom cylinders lost power so I pumped the fuel bulb and they fired up again, I paddled in and checked the fuel pump filter, no blockage. Then I pulled the tops off the carbs and there was not much gas in the bottom carb. I removed the line and carbs to clean them on the bench and I found a little screen, where the fuel line enters the top, (see attachment) plugged with a hairball. Cleaned and reinstalled carbs - all is well. If you've tried everything else and you have these carbs; try checking that screen.

 

[chum1]

Re: Fuel filters

I think there is a service bulletin saying to remove those screens in the service manual, possibly to prevent a lean condition if partially plugged, mine were still in on my 850 when i went through the carbs so i removed them, besides there is a screen upstream in the fuel pump and another plastic filter just outside the fuel tank.

 

[merc850]

Re: Fuel filters

That sounds like a good idea, I'll remove them next weekend. Do you have a copy of the service bulletin?

 

[chum1]

Re: Fuel filters

no but the instructions are in this manual:

http://d01.megashares.com/dl/be222a2/mercury

 

[merc850]

Re: Fuel filters

Great thank you.