[dreamcatchers12]

Just wondered whether anyone has ever heard of prop size affecting the motor. I am currently fighting with dealer about motor missing, dealer said wrong prop on motor. But motor is missing in tank when not in gear. anyone got any ideas. How can you tell one prop pitch from an other. I know that the motor has a rev. limiter but the motor is missing at less than 1/2 throttle.

 

[eimaj]

I can't see the prop size afecting thwe motor that way, it could make the motor lug if you put a hugely over pitched prop on it. But it should run fine when in the tank. The easiest thing to do, would to tell the dealer to chuck a different prop on while in the tank and see how it runs. Seems simple enough. As far as how to tell what prop you have most prop's have a stamped number on them. Like a 8.25 X 13. Or such.

Good luck

 

[dreamcatchers12]

I have 2 props. the stock one has no numbers and the other is 9 x 11. To me they look the same and was just wondering if there was something that I was missing.

 

[steve]

There is a rev limiter on OB's and when they are in neutral the rev limiter will kick in at about 2500-3500 rpm. The reason for this is that there is no load on the engine and that will allow it to over rev in neutral and cause bearing or piston failure. Does the motor miss at idle while in neutral? What RPM is the motor missing at? What RPM does the motor spin at WOT while on the boat in a lake in gear?

 

[MichaelR]

I have to go with cascademarine: there’s too many factors not said and I would add is it a four or two stroke carbureted or injection? Has the dealer put the engine on computer diagnostic and checked out the motor’s brain?

Whatever, prop size is irrelevant. What’s happening is the motor is either fuel or air starved above a certain rpm. It could be a kink in the fuel line or a faulty injector or valve in the carburetor. It could be old gas that deposited varnish in the carb or injectors. There’s so many factors. It could be spark. It could be this or that.

If it hesitates in the tank (and in the tank fuel supplied externally not from the boats fuel supply) we can eliminate fuel supply to the engine so it could be something other than fuel but what is a process of elimination. It could be the spark plug wires are shot. That happens more times than many realize.

If your engine is still on warranty you’re stuck with that dealer. If not, I’d take it elsewhere for a second opinion. I’d call cascademarine or my shop at Brigantine Marine. But it ain’t the prop, guaranteed.

MichaelR

 

[dreamcatchers12]

thanks for all the help. Supplier took back motor for repair. Later said it was the wrong prop. but did replace motor. Still confused about whole deal but there is nothing else I could do. Next time will buy from local dealer and established outboard company.