Nissan help...

[warf]

Need a little help, just got a new 90 hp Nissan, hung it on my flatbottomed 18' jon boat, got the bottom of the cavitation plate 1/2" above boat bottom, has a Nissan 17" prop and after break in it only will turn 43-4400 on the Nissan tac wide open and hit 34 mph, feels a little sluggish on the hole shot. Feels over propped but going down on pitch will kill the top speed but bring the rpm's up. Boat loaded and in the water probably weighs 15-1600 lbs. Any ideas why the poor performance and low RPM's? Motor has about 3 hours on it and still is running the double oil mix...One more thing, this is a boat I just built, marine ply, epoxy, glass, more like a flats boat with flat bottom aft, perfect bottom no hook or rocker and coated with epoxy'grafite mix, very, very slippery.

 

[TOHATSU GURU]

Re: Nissan help...

Is this a TLDI or an old style oil injected?

 

[warf]

Re: Nissan help...

Thanks for the fast come back. It's a new '07 direct injection...

 

[TOHATSU GURU]

Re: Nissan help...

The TPS sensor probably needs to be re-set. Did you do a self install? Also, it wouldn't hurt to try raising the engine the transom. It's trial and error on perfect transom height

 

[warf]

Re: Nissan help...

Didn't do a self install, dealer did it and seems to know what he is doing.Cavition plate is already above boat bottom, I don't think raising it is going to give me the extra 1200 RPM's the motor is suposed to be cranking out, I know it can make a little difference but not all that much. TPI sensor, is that checked with the Nissan lap top the dealers use to set the motor up with?.

 

[TOHATSU GURU]

Re: Nissan help...

The engine cavitation plate can be up to 4 inches above the bottom of the boat on some boats. It's trial and error to determine how high you can get away with. There is no laptop used to set the TPS sensor. The dealer has a code to input by pushing in on the ignition switch and kill switch. Basically you can have a variety of issues that will cause you to not get what the engine is capable of putting out. Transom height, incorrect TPS setting, incorrect propping and incorrect throttle cable adjustment can all add up to a pretty severe performance loss. And last, but not least, running double oil in this engine is a huge no no. It is not done for break-in on TLDI's and will clog up your injector's and foul your spark plugs and is the most likely source of your problem.