I have a 2001 reman with the TCM Energizer starter. When starting, the prop with turn very slowly the first revolution with a loud whining sound, then picks up speed and starts normally. Could that whining sound be the starter at high rpm not fully engaging the adapter or the adapter not fully engaging the crank?

The connection of the starter to the adapter is a blade in a slot, like a straight slot screwdriver engaged in the head of a screw, so that’s not likely to be your problem. Your second guess is more expensive and more likely.

Niagra Air Parts.

Mudwagon wrote:I have a 2001 reman with the TCM Energizer starter. When starting, the prop with turn very slowly the first revolution with a loud whining sound, then picks up speed and starts normally. Could that whining sound be the starter at high rpm not fully engaging the adapter or the adapter not fully engaging the crank?

The starter adapter doesn't "engage" the crank per se like the starter... The gears to the engine are always enmeshed. What adapter do you have? "New" or "Old" style? Did you experience a kickback at all? The old style will break and your dead in the water, while the new style can break and still work (for a while.) The danger would be a broken new adapter, you keep running it, and the engine eats some metal. (bad)

How old is your battery? FW Odyssey or stock in the back? It would be easy enough to swap in another starter and see if the issue goes away.

I forget how far up you are in VT, but if your out and about around Boston, let me know... Swing by and we can pop anther starter in and see.

Greg-

I’m not a mechanic but have a fair amount of time behind IO-520s. What you’re describing sounds like a bad starter adapter. Probably best not to start it until it’s fixed.

It’s an intermittent problem and only when the engine is cold. Had a discussion with a helpful guy at Niagara and concluded it’s probably the adapter.

It’s the old style adapter. Not sure whether to replace with the old or new style.

Mudwagon wrote:It’s an intermittent problem and only when the engine is cold. .....

I've found that pulling a cold engine through a half dozen blades or so first lets the starter turn it over easier.