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I'm restoring a Whaler that has not been in the water since 2002. Got to launch it for my first time yesterday, but noticed it didn't seem to get up and move like it should with full throttle. Sounded like a lot of turbulance in the water. The motor is a 1989 Johnson GT100 model: J100STLCEM. The reason I'm focusing on the prop is that the blades look well worn and I'm not sure its the original/correct one, someone may have stuck a prop on it to sell the boat with it sitting so long. Before I replace it would like to ask the experts here on what is recommended to be the better blade for this size boat and motor. Thanks

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That engine should easily turn a 17" pitch prop on a 16' Whaler. If the engine is a strong runner in good condition, putting out a true 100HP, perhaps a 19" pitch prop.

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Thanks for your input. I got the numbers off the current prop 13x19 last night, in line with what you suggested. Going to take it to the shop to see if it needs replaced or if its still good. Also noticed that half the Skeg was broke off, ordered a Skeg guard/saver and should have it in next week.

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Check that motor is mounted correctly. Top bolts should be in the 3rd hole counting down from the top.

What are the RPM's at wide open throttle (WOT)?

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I'll take a look tonight. Need to hook the tach back up after restoring the center console and will check out the RPM's at WOT also.

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You mentioned the prop blades were 'well worn,' so I must ask, how many blades are there? All kidding aside, a 100hp outboard engine should have that hull moving along smartly. Just like with music, speakers are everything, so the prop will be everything to the boat. My 1975 Newport gets up and flies with a 1986/2002 Johnson 90. Prop is a 3-bladed 13"x 19" stainless.

So please let us know your situation!

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There really is no "correct" prop for your boat - every situation is different. Hull and passenger weight, condition of motor, hull surface, and what you're looking for (hole shot, maximum top speed, waterskiing, etc.) all matter.

Check the mounting height of the motor, per the previous suggestion. On that vintage boat, it would not be unusual to have the motor mounted as low as it will possibly go. If it is all the way down, then you'll need to determine whether the lower bolts are through-bolted, or used the "blind holes" as were many OMCs on Whalers - if so, you won't see the lower bolts at all on the outside of the transom. If it was mounted using the blind holes, it's a bigger deal to raise the motor, so you'll want to decide if it is worth it to you - depends on what you want to do with the boat long term. The low mounting may well have contributed to your feeling that it wouldn't go as fast as expected at full throttle.

These two articles may help:

http://www.whalercentral.com/articles...icle_id=82
http://www.whalercentral.com/articles...cle_id=106

Can you clarify the condition of the prop, and whether it is aluminum or stainless? If by "worn" you mean that the paint is worn off, that's not necessarily the end of the world - but if it's all bent and dinged up that's a different story. Many OMCs used the OMC SST painted stainless prop, and the paint wears off them over time. It's not a bad prop, but technology has moved on so you can do better if you're really looking to optimize.

Tim

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Sorry for the long delay on this post. I had a large honey do list to finish before I was allowed to playing with the boat again. So, after further investigation, although my prop has some wear, it was normal wear for the age and use. What I did discover was that most of my issues were carb related. Besides the carburetor linkages at the Air Silencer base working loose, the carb needed a major cleaning. Once I tour apart and cleaned the carbs, fuel lines, blew out the check valves for the High speed & low speed vacuum/fuel lines and replace a cracked chock valve, the boat ran great. Based on the GPS was able to cruise about 42 mph WOT. All is great!!