1990 90 hp johnson need a little help

[wisemack34]

I install the 90 hp johnson on my 17' center console boat today....& runs great But coming out of the hole is bad....I put a 17 pitch prop on it.....You guys think if i put my 15 pitch prop & whale tail on it.....would it help it out of the hole.........I forgot one more thing....What kind of RPMs i should have taking off....today with the 17 pitch on it was like 3000 rpms.......

 

[tashasdaddy]

Re: 1990 90 hp johnson need a little help

was your trim tucked all the way in? then trimmed out? that thing should fly out of the hole.

 

[ob]

Re: 1990 90 hp johnson need a little help

Also insure that engine isn't mounted too low on transom.Anti ventilation plate of lower unit should ride even with or slightly above boat bottom.Also I don't follow what you mean about 3000 rpm on take off.Is that the rpm at which the boat gets up on plane?If so,then that's about average.What rpm will the engine turn at wide open throttle as propped pushing the rig?

 

[wisemack34]

Re: 1990 90 hp johnson need a little help

Ok,,When i push wide open on take off....it reads 3200 rpms....after it planes it will run what ever rpms i want 5600 rpms.....I just thought that it should plane alot faster take about 70' for it to plane.....with just me on the boat....

 

[Dennisanoka]

Re: 1990 90 hp johnson need a little help

I have a 89 90hp, different boat of course but It looks to me like you are in pretty good shape. I believe 5500 is recomended max. wot. How you get there won't be found in any manual. I did just raise my engine 1.5" so that my Cav plate is .75" above the hull line and it did a few things, it improved hole shot, reduced bow raise on take off, and brought my RPM's at WOT up to 5500.(trimmed out) If you have 5500 with the 17 and you go to a 15 your RPM's may be too high at WOT and your top speed will drop at 5500. It would improve the hole shot but them you'll have to watch the wot rpm's and you'll give up speed. I use a 13x17 and a 13x19 aluminum Solas but I may have a lighter boat.

Just my 2 cents

 

[wisemack34]

Re: 1990 90 hp johnson need a little help

Yeah...when i take off the front off the boat it way up in the air.....

 

[Dennisanoka]

Re: 1990 90 hp johnson need a little help

There is a bar that the engine rests on when you lower it. Is that bar all the way forward?

 

[tashasdaddy]

Re: 1990 90 hp johnson need a little help

transferred from other post.
keep your post together, some answered this in the other one. fuel hose is the same. set up is 90 % of preformance. was the 70 a short shaft, and 90 a long shaft. that would make a major difference.

 

[Dennisanoka]

Re: 1990 90 hp johnson need a little help

If it is all the way forward( first holes) is the engine resting on it? Obviously the motor should not be trimmed up at all at take off. Weight distribution in the boat makes a huge difference. The more weight in the back the more bow raise. I have a spare 6 gal. tank in the back and a spare trolling motor battery. If I take them out it makes a big difference.