Few Johnson 115 questions

[dave]

" I just finished rebuilding m

" I just finished rebuilding my first outboard and it seems to run fine. One thing im not sure of is there supposed to be water spraying out of the 2 holes on the shaft where the exhaust comes out?

I cant seem to get the linkages hooked up right i mean its close but still needs tuned right. Do i adjust the cable from control first, then the carb cam lever, then the idle screw or what? not sure what order to do them in.

Also how does a trim gauge hook up, mine doesnt work and i would really love to get it working again, and is there any way to test it?

Also i have this 115hp motor on a 1981 skeeter 17 bass boat. I can only get it to 41mph, i was wondering if that is a little low or what i should expect?
If i trim it up i can get it to maybe hit 42 but my rmps get up to 6500+ so i dont like to do that i was wondering if i just need to keep it trimmed down or get a bigger prop.

The prop i have on it is a 13 3/8 inch 17 pitch SS prop. I also tried a 13" 19 pitch aluminum prop but i couldnt notice any top end gain, and seemed to take longer to plane out. so i put the SS one back on. maybe 41 is what its supposed to run at =), its good with me i just want to make sure the motor is running right.


Thanks
Dave "

 

[joereeves]

"Dave... Test the trim gauge b

"Dave... Test the trim gauge by making sure that 12v is being applied to the proper terminal, then ground out the sensor terminal of the gauge. The gauge should peg to maximum if it's okay.

The top rpm of that engine is 5500 rpm. Anything over that is inviting a thrown connecting rod! It hits its horsepower at 5000 rpm, and full throttle is considered 4500 rpm to 5500 rpm.

Linkages:
(1) Back out the mechanical idle stop screw, get it away from the block.
(2) Make sure that the linkages between the carbs are as they should be, not one throttle butterfly slightly open, one closed etc. They should open and close at the same time.
(3) Align the scribe mark on the cam so that it contacts the center of the carburetor roller. Not before or after. Do this by adjusting the roller one way or the other. If you've changed the cam on that threaded shaft, put it back where it was.
(4) Run the engine and set the idle by adjusting the trunion on the throttle cable (where it clamps in the motor). If your engine is a 20" shaft model, set the idle (on a flushette) at 1000 rpm. If a 25" shaft, 1200 rpm.

When you get the idle rpm where you want it via adjusting the throttle cable, screw the idle stop screw in just so it touches the block.

Joe

"

 

[dave]

" Sweet Joe thanks again!!!

" Sweet Joe thanks again!!!

Im so happy with this boat, i cant wait till its going smooth im almost there =).

Dave "

 

[dave]

" When i take off my boat plan

" When i take off my boat planes out real good, but then after i plane out i trim it up some, not sure cause of the gauge is broke, but anyways my mph doesnt go down any it still sticks around 40-41 but my rpm goes way up to 6400 i didnt notice it till i looked down and slowed the motor down.

I currently have a 13 3/8" X 17p SS prop on it, Should i go up to a 21p prop so it would drop my rpm down to about 5400? would that help my top end speed? Im wondering if this is why my boat only does 40 mph with a 115 and my friend has identical boat except his is 19' and not 17' like mine. He has a 150 evinrude on his and his boat does 65mph!
Just seems like mine should do 50.

I tried using a 13" X 19p alum prop on it but seemed to be harder to plane the boat out and still could only get 41mph out of it. I think its cause aluminum bends in the water making it equal to a 17p SS prop.

Thanks again
Dave "

 

[jon]

" Dave,

I'm not

" Dave,

I'm not sure if there is anything there that is limiting RPM's, but 6400 is very high; you very well may be loosing top end by having the wrong prop, running it at 6400 RPM's is also not a great idea for the engine. Check out the michigan wheel website @ www.miwheel.com . There they have a prop calculator that will give you a ballpark estimate of what pitch in stainless or aluminum will be right for your setup.

Jon "