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Boat Repair/20hp mercury prop will not turn on forward

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Expert: Jeff Grigg - 2/22/2008


Question
I have a 20hp blueband mercury. i know the motor is old but i have just spent a fair bit on getting her to run which it runs and idles ok.
my problem is the prop will not turn! I just bought a brand new prop and fitting kit and it still wont turn. i just checked the actual shaft and it free spins on forward but engages on reverse turning manually.
Any help and advice will be greatly appreciated
Cheers
Brad

Answer
Brad either the linkage is wrong or a problem in the lower unit. I suspect the upper and lower shift shafts are not aligned properly. Remove the lower unit. Shift the engine into neutral. Manually shift the lower unit into neutral, turning the shift shaft cw and ccw from neutral should give you forward and reverse gear. Put it back into neutral and put the lower unit back up.
Post back if needed.
Jeff

Boat Repair

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Jeff Grigg

Expertise

Can help with most any question related to outboards, high performance, hull repair, rigging, if it floats and uses a motor. From a 9.9 on a aluminum boat to DFI two strokes. Outboard motors are my specialty. I can help with some I/O questions as well. Ratings are the only way we know if we are helping. If you are pleased with the help, please rate us. 20% don't bother reading my answers! If you are not going to read the follow up then why ask? Keep in mind we do this at no charge and are not paid. We do it to help you!

Experience

32 years in the marine business. Own a service facility, in coastal South Carolina certified Master Tech by Johnson/Evinrude, certified Mercury/Force, Tohatsu/Nissan. Former technical director for DMI Pistons. 30 year racing career including 3 APBA Formula V National Championships

Organizations
AMTECH, APBA

Publications Written For
Boat & Motor Dealer, Car Classics, Custom Vans (tech articles), Miami News, powerboat racing column

Awards and Honors
Certified Master Technician Johnson/Evinrude

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