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90hp Merc ELPO bogs under load

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Nelson B

New member
[h=2][/h]
Hi,
I took our pontoon boat with a 90hp Merc. 2 stroke outboard out for it's first Spring run and it kept dying under load and was hard to re-start. I assumed there was water in the gas as the tank was left 1/2 full, so I added drygas and filled balance of tank with fresh gas. It started a little better and idles in gear OK, but when I call for any more speed/power, it just stalls/bogs down; re-starts fine. What's more likely, dirty carburetor/chokes or fouled plugs? I'm not familiar with 2-stroke outboards, but am familiar with 2-stroke snowmobiles; that's why it seems like either fouled plugs or dirty/sticking chokes, dirty/plugged high speed jet - however, none of these issues ever seem to stall/kill the motor in a snowmobile. Please help!! Thanks!!! Nelson
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Since you have 2 cycle knowledge start w/a fresh set of plugs. If this engine is a 4 cylinder it is a 2+2 engine whereby it runs 0-1800 RPM on the top two cylinders. At around 1800 RPM the bottom 2 cylinders should kick in as they receive fuel from the high speed jets. I suspect that they are dirty like mine were. Drain the fuel from the carbs or run them dry. Remove the fuel line from the tank and drain it. Insert the hose into a can of Seafoam and pump the primer bulb until the carbs are full. Let the Seafoam soak for 48 hours w/the engine upright. Start it up in the water; it will smoke like a banshee until the Seafoam burns off. Run it like normal...you should have better idle and throttle response.
 
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