85 johnson advise

[buzzking]

i have a 16.2 tri hull challenger bass boat with a 85 johnson. I bought it from someone who had be pleasure boating and had a 17 pitch on it to get a big pickup. he also give me a 19 pitch the 17 runs 35 gps and the 19 runs @40, can i get more out of a larger pitch without losing decent pickup?

 

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Re: 85 johnson advise

Hi, buzzking. Welcome to iboats.<br /><br />I'm not the prop whiz, but can advise you to test by tachomweter. Your engine should be able to run at a certain RPM at full-throttle. If the engione is in prime tune, and you cannot turn full RPM, you are overpropped. If you can exceed tghe Max RPM, you are underpropped.<br />So really, to know for absolute sure, You'll need a tach,and a tune-up,and a few test runs.<br />My guess is, the previous owner has asked his shop's tech for a better hole-shot,vs a higher top end for pulling skiers out ect. Chances are, the larger pitch prop will serve you fine, but do check to make sure you can get enough RPM. If not, you are loading the engine more than it was designed to be loaded. But standby here, we got several very bright prop gurus that may post additional help.<br />I just wanted to greet ya, and give you the basics.

 

[ob]

Re: 85 johnson advise

buzzking, You will definately need a tach to verify rpms if you don't already have one.Your engine WOT rpm range is 4500 to 5500.I would recommend using the prop that will allow your engine to turn up in the upper range nearer the 5500 mark.Throttle response will be crisper and engine will last longer.