Can't get full throttle - 1959 super seahorse 35

Hello all,

I recently replaced the carb's gaskets do to a leak and thoroughly cleaned the entire carb. Upon putting the carb back on and starting it up, it idled great. However, at full throttle, the boat goes 5 mph tops when it went 20 - 25 before the cleaning. I'm quite positive it is not a linkage problem and I highly doubt that there is some blockage in the carb. I have since sprayed carb cleaner through with no result. I spent a good amount of time adjusting the needles with no luck. So my question is, where are some places to start besides a cleaning and looking at the linkage. When I did the cleaning I did take out the high speed jet, which I noticed was not completely screwed in (not sure how far, 2-3 turns max). I have since tried it completely seated ans backed off a little with no better result. Not sure if that will have anything to do with it but anyway, any advice would be greatly appreciated.

Re: Can't get full throttle - 1959 super seahorse 35

The static setting on the high speed needle is 3/4 turn out from lightly seated and then fine tuned on the water.
Have you checked to see if you have spark on both cylinders?

Re: Can't get full throttle - 1959 super seahorse 35

The needle position Isn't the problem I dont think. I spent a while fiddling with it. What i was referring to was the If the high speed jet should be screwed in all the way or not. I noticed a pin hole about halfway up the jet. does that need to line up with anything?

Re: Can't get full throttle - 1959 super seahorse 35

Are you talking about the nozzle that goes up through the center of the body, it should be screwed in tight.

Re: Can't get full throttle - 1959 super seahorse 35

Ok I wasn't sure because it wasn't when i took it apart at first. any thoughts on what could be causing this?

Re: Can't get full throttle - 1959 super seahorse 35

Question, is the float installed correctly and adjusted properly, just trying to think of possiable problems.

Re: Can't get full throttle - 1959 super seahorse 35

Yes, it installed properly and is level with the top of the carb body. The float valve is functioning properly as well. I currently have it apart. One thing I am not sure of is weather or not any sort of gasket is associated with the high speed nozzle. This link shows no "http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1959&hp=35&model=RD-21&manufacturer=Johnson&section=Carburetor+Group" However, when I look at webpages detailing rebuilds of these types of carbs there is usually a "boss" gasket at the bottom or maybe even one between where the nozzle actually screws into the body of the carb.

Re: Can't get full throttle - 1959 super seahorse 35

That particular carburetor does not require a boss gasket around the main nozzle, but it won't hurt if you put one in anyway.

Get your eyes off the carburetor. That is not the problem. It is running on one cylinder. An ignition problem, probably.