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Woops - props on backwards....but ????

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Old 05-23-2007, 12:29 PM
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Default Woops - props on backwards....but ????

SO my 4-blade cleavers couldnt get my boat on plane and I found a buyer so I sold them and will keep hunting....after work I pulled them, polished them up a bit, packed them up and I get a call from the wife that freinds are in from up north and could we give them a ride tonight? I dive in, it's getting duskish, I'm rushed...

Long story short - I put the wrong (original 3-blade) props on the wrong arneson shafts. We have a nice dinner - couple of drinks, jump on the boat, fire it up....put it in forward and it goes backwards...no worries, I'll say nothing and just shift backwards all evening since it is just a slow ICWW cruise.

So as I'm cruising along - questions start popping into my head:

1) The transmissions are borg warner 71Cs and are running backwards to make forward motion....they have a 1.5:1 reduction stamped on them yet my speed at 1000 rpm is normal (gps 8 mph).....does that make sense?

2) So I figure, ok, maybe at 1000 rpm the difference is not too obvious. I'll see if it will get on plane and what speed I see at 3500 rpm....runs fine, planes fine, same cruise speed as in "forward". WTF?

3) So do I have straight 1:1 transmissions that are mismarked (rebuilds BTW) or does the tranny do it's reduction magic in both directions somehow?

Wuzup with this thing?
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Old 05-23-2007, 12:31 PM
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burned mines running that way with TRS...
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Old 05-23-2007, 12:56 PM
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Potentially Swamp...I would call Rik at Arneson.

Julie
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Old 05-23-2007, 02:08 PM
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The clutch pack for reverse is much smaller and will let go with time. Reverse is reduced on Borg Warners. It think it is 1.5 to 1 and since you have a 1.5 to 1 trans you are probably the same ratio in forward and reverse. Not 100% sure on that. But 100% sure swap those props back.

Last edited by Brad Zastrow; 05-23-2007 at 02:14 PM.
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Old 05-23-2007, 02:15 PM
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You are asking for big trouble running your trannies in reverse (to go forward) I'm surprised they lasted this long.
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Old 05-23-2007, 02:36 PM
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just did it for 2-3 minutes last night - swapped them already this morning. Brad - your comment would explain it. I have no intention of running them backwards folks - just seemed odd that it was the same speeds at the same rpms.

Thanks!!
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