What limits the RPM and what is safe to Spin to? 7.4L
05-22-2009, 12:57 PM
#11
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I could be wrong here but I do not think merc was doing rev limits yet in 1986, Do you have a old manual of any kind laying around or do you still have the OEM flame arester on the carb or any old stickers on the engine that would say what max RPM you should be running at when it was still stock that will give you a starting point, To me 4300 just sounds a little to low of a RPM.
also I did not mention the exhaust internal flappers were all fouled and sticking closed, the new tips will have external flappers
05-23-2009, 07:34 PM
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Well boy was I wrong, I watch the tach today while doing a full throttle run and it hit 5,500rpm's! Should I consider a prop change? I do have a 3 blade SS prop (not sure on the pitch but I can check) maybe a 4 blade prop??Sorry for stealing this thread but just a simple question.
Thanks
Erik
Thanks
Erik
05-23-2009, 08:03 PM
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Do you think I can benefit from changing my 3 blade SS prop to a 4 blade? What is the con's and pro's? I will get the pitch size tonight on my 3 bladed SS prop thats on it now.
Erik
05-23-2009, 08:06 PM
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Well boy was I wrong, I watch the tach today while doing a full throttle run and it hit 5,500rpm's! Should I consider a prop change? I do have a 3 blade SS prop (not sure on the pitch but I can check) maybe a 4 blade prop??Sorry for stealing this thread but just a simple question.
Thanks
Erik
Thanks
Erik
05-23-2009, 08:14 PM
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Its funny because when I had it out Wensday I thought I only seen 5,000 rpm's on the tach but today she spun up to 5,500rpm's. Now the only diffrence from Wensday to today is Iam running the fuel tank down to empty, but also I had my sister in the boat. So less fuel but an extra person.
Will prop change in pitch and going from 3 blade to 4 blade help mph?
Erik
Will prop change in pitch and going from 3 blade to 4 blade help mph?
Erik
