1996 Nitro 170TF Rick Clunn - Prop Questions

[Just Run]

I have a 1996 Nitro 17' 170TF Rick Clunn edition with a Johnson Tracker Pro Series 115hp on it that I bought last year, and I am having motor plane issues with. If it is just me in the boat, it takes a few seconds, but it will jump up on plane and hit 50-60 mph no problem. However if I add anyone else to the boat, it won't do it unless I move them to the front, once on plane they can move back to the seat. I did take it in to be serviced and the mechanic said everything checked out and was within spec, however without knowing RPM's he couldn't tell me for sure what the corrective measure is. It has a 17" 3 blade propeller on it with a HydraFoil, and he mentioned I would likely need to go down to a 15" prop. I have a buddy with the fish/ski version of my boat, and I know they sit more forward, but he has a 21" prop on his and has never had plane issues. I have (3) group 27 batteries in the back, and other than some of my tackle, most everything else is in the front. Any idea's if going down in prop size will help this or if you have seen this before? Thanks in advance!

[omcforever]

First of all, you may be seeing 50 when its running right/set up right but not 60, put it on a GPS and you will be surprised especially with a 17 pitch prop and at 4200-4400 rpm as you stated in the OMC forum. If you are having to drop to a 15 pitch to get on plane then you either have motor issues or toting a LOT of weight....that boat should run 45- 50 at 5500-5700 with a 21 pitch prop depending on load.

[ECobb91]

^^ what he said. I have a 2003 nx750 with a 115. It’s half a foot longer and a little wider than the clunn edition but I’m lucky to get 48-50mph. At 4500rpms mybbet is it would be running around the low 40s. A buddy has the same boat you do with a 115 and he runs 43 with a 21 pitch prop.

check the fuel lines. I ran into a similar issue where when you hammer down the boat would just plow the water and rpms wouldn’t get above 2500 for about 10sec then it would take right off and my compression numbers are all perfect. . One of the main causes of it was the fuel lines were deteriorated due to ethanol and caused fuel restriction. Once the lines were replaced my holes shot still sucks but the motor doesn’t bog down anymore and don’t have as many issues getting on plane. If your compression is good, it could be a fuel thing. If it’s not fuel or compression related then it’s a weight distribution issue

[moetorola]

I had a 170dc I carried two props.

By myself I ran a Raker 20p 13spline around 52 to 54gps @ 5500rpm Fall and Spring
With a passenger or heat of summer I ran an Raker 18p 13spline roughly 47 to 50gps.

I always kept the boat lightly loaded with gear and ran 2 batteries. And typically only half to 3/4 tank of fuel. I weight about 180.

Was a great boat, cut thru chop for a 17footer pretty good.

Raising the engine made an improvement all around. From the factory back then, they set the engines all the way down.