DUI and Acme prop
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=3482
Printed Date: November-23-2024 at 9:55am
Topic: DUI and Acme prop
Posted By: TRBenj
Subject: DUI and Acme prop
Date Posted: April-30-2006 at 7:28am
Thought I might chime in with my success yesterday after installing my DUI from Performance Distributors and a new Acme prop. Unfortunately, my results arent fully documented as I never had the chance to check the timing with my stock distributor before my ignition module quit. The motor is stock (with the exception of the DUI), 240 horse 351w with the 1.23:1 Power Plus transmission. I havent calibrated the speedos, but they should be pretty close.
With the new DUI, I set my base timing to about 14 degrees and made a few small carb adjustments. Doesnt start hard or ping under load. Picked up 200 RPM and 1 MPH on the top end (42 1/2 @ 4400). Felt very strong.
Added an Acme #470 prop, gained another 200 RPM and 1 MPH on top of that (43 1/2 @ 4600 RPM according to my speedo). Felt smoother throughout the range and the boat really jumps out of the hole.
Overall, a big improvement as I was only getting about 41 MPH @ 4200 RPM with the stock distributor and 4-blade OJ. I havent opened up my plug gaps yet (Performance Distributors recommends .050" - .055" gap). Ill report back with any changes once I do.
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Replies:
Posted By: TRBenj
Date Posted: May-01-2006 at 10:41am
Quick update:
I opened up my plug gaps to about .056" yesterday. Gained a touch more RPM, maybe 50.
Very happy with the results this weekend!
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Posted By: tjackle
Date Posted: May-02-2006 at 9:51am
Is your motor a LH rotation?
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http://www.correctcraftfan.com/diaries/details.asp?ID=1520&sort=&pagenum=1&yrstart=1976&yrend=1980 - 78 Nautique
If you're going to do it...
Do it in a boat
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Posted By: TRBenj
Date Posted: May-02-2006 at 10:31am
Yup, its a standard rotation motor. The rotation direction is reversed in the 1.23:1 tranny, so the boat runs a RH prop.
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