RCV 90 SP starting procedures...
 

Is it OK to start this engine from the front using a spinner and a starter motor...? by pass using the starter at the back over the gear? If using the built in starting port ...will it be OK to use a small power screwdriver? Thanks...

G'day Richard,

It's not the done thing to reply on a manufacturers forum but since they haven't been on here since 2007 or so, here's my opinion for what it's worth.

Yes you can start the engine from the front using a starter motor. But due to the 2:1 reduction gearing you will require twice the torque to turn the engine over compression, and there will be twice the force making the starter slip on the spinner. The good news is that the crank shaft and piston will be turning at twice the speed of the starter so it should start well, assuming you have the torque to turn it over compression. You might need a high torque starter.

The manufacturer doesn't recommend electric screw drivers because they generally don't run at sufficient rpm to start the engine, or if they have the rpm they won't have the torque. But if yours does have sufficient rpm and torque then it should work fine.

The trick when using the rear starting port is to not release the starter button or trigger when the engine starts, if you do the engine will be driving the starter. This is hard on the engine and makes it difficult to slide the starter wand out of the engine's starter screw (electric screwdrivers and drills are worse in this regard). Instead remove the starter while it is still powered then release the button (easier said than done).

The rear starting method is by far the easiest and safest if you have a starter and the starter wand adaptor (is it still available?), don't forget to reverse the battery connection to reverse the starter direction though.

I start mine by hand using the back flip method to bounce the engine of compression. The engine starts very easily as long as it has been primed correctly. The back flip needs to be done correctly so that your fingers are clear of the prop before the engine hits compression though. I don't recommend it unless you know what you are doing (I see many people back flipping with their fingers still on the prop as the engine hits compression).

Good luck,

Dave H

One issue with an electric screw driver is that it is not a clutched drive like a starter. That means, if you use a screw driver to start the motor, a lot of times, when the engine starts, it's rotational speed will be faster than the driver, which can cause the starter screw on the top of the crankshaft to break loose and unscrew. Yes you can use a starter on the spinner. Yes it does take more torque.
As a result, it's very easy to scuff the spinner.

I've had very good results starting the SP-60 from the front with an ordinary Sullivan starter and a small 4.5A battery. It really behaved just like any other four stroke. For the 90 you would need more juice, I think. Jim