From: Lee Shuster <Lee.Shuster@...>
Date: Mon, 24 Aug 2009 12:47:30 -0600


Let's take a shot at answering your legit questions (my responses in RED):

>SAFETY: Is the main issue is that the engine can accidentally be
>started while in F or R right? Or is there another safety concern?
>Because with a 3 wire switch, I would still have that same safety
>issue. What's the difference?

NO, this is not the main (safety) issue. ALL OMC BOATS built before 1969 have no (5-wire) NEUTRAL-SAFETY interlock. They all had the 3-wire switch and they COULD be started at WOT (Wide-Open-Throttle) in either GEAR (F or R). Great for dock bustin' and throwin' operators overboard! So, the "safety" issue I'm concerned about is largely an ergonomic issue: The operator's ability to simultaneosuly juggle and seemlessly control steering inputs, throttle changes and gear changes, safely and smoothly in any traffic or weather conditions. Your comment, "Yes it's a little weird, but it went ok," probably alludes to my concerns. You might get away with it under very controlled test conditions, but it still falls into the "Don't try this at home, folks!" category. This is eactly why the OMC shop manual section I sent out over the weekend, instructs one to do "Dry" testing (on land) with the Ign key on and the remote control engaing a forward or reverse selection. You then simply walk to the back of the boat and gently rotate the prop to verify clucth engagement. Safe and simple!

>MECHANICAL RISK: Is it the risk of accidentally switching while
>underway? Tripping the switch at too high RPM? If so, makes
>sense. But If the factory switch was working / installed properly and I moved the shift lever from forward to neutral to reverse >- what happens with the engine RPM when it goes into neutral for that second
>or two? What's the "safe" max RPM to shift around?

Yes. Yes. Nothing bad. And anything under 1000 RPM, shooting for 475 to 625 would be ideal. So any exposed toggle switch, especially on a boat in rough seas has the potential for being accidently bumped or activated. That's why they invented, spring-loaded toggle switch safety covers, commonly seen in aircraft. If you accidently "release" the engaged clutch (shift to neutral or remove power from the coil) under power you risk extreme over-revving. (An electronic engine rev-limiter would be useful, here.) Accidently, engaging the clutch coil above 1000 RPM is also stressful, greatly reducing the useful life of the lower gear case, and possibly risking damage. (A programmable, electronic low-RPM threshold rev-monitor could be designed to prevent that.)

You see, there are very good reasons why OMC engineers integrated the throttle, shifter switch a START/IDLE functions into one cohesive, ergonomically designed unit. When you rig up an alternative work around and take it beyond your driveway or test bench things can change as quick as the weather in the Utah mountains!

>Am I forgetting something - or are those the two main concerns? I
>absolutely don't want to damage my engine. I'm fine with launching
>myself out of the seat through the windshield and into the water by
>accidentally changing gears at high speed, but I'm not fine with
>damaging my engine.

Speaking of being thrown out of a powered craft and into the water -- If that un-attended power boat that you get thrown out of circles around, (as they usually do) you better hope you installed a Man-Overboard Safety Switch cutoff! You know, the little red tethered cutoff switches, like you see on new boats and jet-skis. I hook mine up, especially if I'm in the boat alone or in rough water. I also carry a spare and taught my wife where it is and how to over-ride it. Engines can be easily replaced, but your life and limbs cannot.

>That was 1/2 the problem with the new switch. Just as the manual
>says, the little roller was slipping out of the slot. Quite a
>challenge seeing that happening when everything is closed up and
>hidden in the housing. Used my x-ray vision.. The other 1/2 of
>the problem I guess I didn't explain well enough was that even when I
>was holding the switch in my hand and testing it with the light, it
>only lit up in neutral and reverse positions. Not forward.

Something isn't making sense to me here. A) You may have a defective switch or B) You may have mis-read your testing procedure.


Logically RED (Purple on later OMC's) is your INPUT to the switch and you outputs are either (F) GREEN or (R) Blue. Make sense?

IS it possible you misread your indications? Perhaps confusing the FORWARD and NEUTRAL WIRES/CONTACTS?
Did you see a symptom that would not allow you to take the gear case out of neutral.

Jeff, sometimes I find it helpful to look back at the original symptom, and document everything I've done so far.
It's not clear from this e-mail what the current outcome of your testing is. Could you actually successfully engage F and R clutch coils?

Good luck and keep at it. Hope this with helpful to all.

Received on Monday, 24 August 2009

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