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1985 OMC 43 Stringer Top Speed

gmcelroy

New member
I have my 18 foot Marlin compl

I have my 18 foot Marlin completely tuned and took it out on the water today. The top speed was 45MPH at 5600 RPM. While I think 45 MPH is fine but I am concerned about the RPM's. Should the boat be pulling 5600 RPM's at the top end??
 
"Good speed but I would say yo

"Good speed but I would say your about 1000 RPM too high. Are you sure the tach is reading correct? Do you have or can you borrow a shop tach to verify. What size is the prop, you might be under propped but you would have to increase the pitch quite a bit to bring the rpm's down that much."
 
Bob....I just installed a Petr

Bob....I just installed a Petronix pointless ignition....Do you think it's throwing the tach off a bit??
 
"I'm not aware of any prob

"I'm not aware of any problems like that, the tach still gets it's pulses off the negative side of the coil. What about before the upgrade, did the rpm's go that high?"
 
"Ok then...all the more reason

"Ok then...all the more reason to get a second opinion using a shop/portable tach, double check at idle and WOT, you would like to be around 550-600 at idle in gear. Who knows your dash tach might be reading wrong, there is usually a switch on the back to set it up for 4, 6, and 8 cylinders."
 
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