A smaller prop?

[greatlakestate]

I recently converted a K&B nitro outboard to run an electric motor. The unit came with an Octura x440 and was intended for the nitro set-up, which I beleive may be too large for the Monster Marine motor that I will be running until I eventually go to a larger brushless motor. Do any of you have a suggestion as to what size I should try (shaft diameter has to stay the same as the x440, but I'm looking to drop the diameter to take some load off the electrical hardware.) I haven't tested yet so I am just guessing that the x440 is too big. This will be on a 30" deep vee.

Thanks!

[Fluid]

We have to know the specs on the motor and the voltage at which you will run, along with how deep the prop will be run (surfacing or submerged). I can't remember the exact specs on the MM motor, but it won't like running on more than 8 cells/3S power. It is really too little motor for a 30" hull. But you are right, the x440 is probably too much prop. I'd start with a y536 or an x438 prop. An OB puts more strain on the motor than an inboard setup does.



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[greatlakestate]

Thanks,

I'll look into those props. I have no idea on the motor specs (neither does any other on-line source) and will be running just 6 cells to start. It is an outboard so I'll be running submerged, I'm going to raise it as high as it will go. Prop level will be just below of the bottom of the transom. I'll see what that gets me.

Yeah, It is a small motor for a 30" inch hull...crappy economy, family to support on a tight budget...you get the picture. I had a parts bin from back in the day that I have been working out of and aside from some odds and ends, an ESC will be my only purchase until I can get a better set-up. I'll be happy if this motor gets me on the lake this summer, even though performance will be more like scale speeds, etc. This old prather hull used to do about 40 as a nitro... I just got sick of the amount of effort, smell and mess that goes into running them.

I plan to cool the ESC and probably the motor as well to keep temps down with the extra load of a larger hull...if I can get a summer's run out of this I'll be happy until the holidays roll around. Thanks!

[greatlakestate]

Forgot to mention - I do have an x437 3 blade that I purchsed as an upgrade for a semi-RTR deep vee kit back in the 90's. This boat did fine with it running a single stock factory motor Still too much?

[jcald2000]

The rule of thumb is adding a third blade is the same as going up 5 mm in size on a 2 blade, so NO it is the same as a 442 2 blade.