one cylinder dead (reeds)

[alan chandler]

I just purchased a used boat with a Nissan 40 hp 2stroke. I'm not sure, but I think the motor is a late 90's model. When I put the boat in the water, it would not get over around 1500 rpms. When I pulled the top spark plug wire the motor died. When I pulled the bottom spark plug wire the motor did not change at all. It was running on the top cylinder only. I brought it home and pulled a compression test, Spark test on the wires(coil), and a test on the plugs. Everything checked out so I knew it must be fuel/carb, but could not figure out how just one cylinder with it being a single carb engine. When I pulled the carb to clean, I noticed the reed boxs in each side of the intake. Carb was clean. but on the left reed box the bottom reed has what appears to be a piece of the actual plastic body/box that has disformed or melted and may be not letting the reed close or air/fuel travel past properly.<br /> My question is what is the simplest way to change the reed box and do they make after market high performance reeds? Or do ya'll even think this is the proper diagnosis? Thanks

 

[TOHATSU GURU]

Re: one cylinder dead (reeds)

There are after market reeds available and that could be the trouble. Unbolt the manifold and there they are.

 

[alan chandler]

Re: one cylinder dead (reeds)

Thanks for the info. I believe that I am going to go ahead and pull the carb again tonight, along with the manifold, just to go ahead and replace the reeds. If I remember correct they were not expensive for dirtbikes. Thank you again and take care.