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305 2 barrel

homerl

Regular Contributor
"My 187 scorpion 1986 is runni

"My 187 scorpion 1986 is running well.I believe it's running in the 45-50mph area.I have a 21" stainless prop on it,but the rpm's never seem to get over 3500.Have checked and the throttle flap at the bottom is opening all the way.Boat gets up to speed very quickly.Is 3500 normal because I hear alot of talk here about 4200-4500 wot.Not complaining,just wondering.

thanks dave"
 
Tach may be off if your boat i

Tach may be off if your boat is traveling that fast. Do you have a GPS to track your speed? Try to borrow a hand held engine analyzer w/a tach from AutoZone to check your tach.
 
"Thanks guys,but are tach'

"Thanks guys,but are tach's known to be accurate at idle then loose accuracy as the rpm's increase?Would this be one way to tell if it is starting to fail?"
 
Definitely your tach.
At 50 m


Definitely your tach.
At 50 mph with a 21" and 1.50 ratio drive you have to be turning in the low to mid 4000's rpm area.

Rod
 
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