Swap broken 1996 Force 120 with 1996 Johnson 115 outboard - any tips???

[batman99]

Update:

- Added keel guard / rubber protection strip - this item works great.
- Rotated its fish finder's transducer mount - to reduce water spray. This worked great

After a few on water trips, I'm still tweaking a few things. re:
- Removed the 2nd alarm connection (that I accidently wired to Aux power wire).
One alarm (for engine over heating) should work fine.
- Plan to buy / install a 4-blade 16 pitch aluminum - which runs like a 17 pitch with more grip.
- Use its current 3-blade 15 pitch as an emergency spare.
- Raise it's motor 1 bolt hole - to reduce some water splashing from its too deep cavitation plate
- Replace broken driver's seat base with much better steep plate base.
- This spring, ask my boat mechanic to do a formal link&sync alignment.

Overall, the used 1995 Johnny 115 V4 on my 1996 bayliner 1700 LS works great.

Just a few minor tweaking things and it will be perfect. Giant smiles...

 

[emdsapmgr]

You will want to prop that engine to run in the upper rpm range of the factory stated "normal operating range." So if the factory says the normal operating range is 4500-5500 rpm's. So you will want to prop it to run at 5500 with a light load at full out trim-WOT. If the engine is an "intruder or faststrike" variant, that 115 engine is rated to run between 5000-6000, so you'd want to prop it to run close to 6000 rpm's.

 

[batman99]

Thanks for your feedback emdsapmgr.

I also noticed this normal brand of 1995 Johnson 115 V4 engine runs best when its RPMs are > 3,500.

Its sweet spot seems to be around 4,000 rpms (re: Its RPMs are comfortable without being too loud).

If wondering, I got its new seat base back from welder guy yesterday. Cannot wait to try it this weekend.

.

 

[batman99]

Update:
- Seat's welded steel base works great.
- My customized wiring works great. re: toggle switch for main 12v dash & Lighting and OMC control key for its engine ignition.
- new aluminum Solaris Amita 4 blade @ 15" pitch prop works great.
Note: This prop feels like a 3-blade @ 17" pitch with much less slippage (especially during hole shot)
- Engine mounted 1" (1 bolt hole) higher on transom works great.
- Installed 1995 Johnson 115 V4 works great at 4,000 rpms (its RPM sweet spot)
- Engine runs perfect with 2 man tube at max 4,500 rpms.
- my normal cursing RPM speed with 2 adults and 1 child in boat is between 3,600 -> 3,900 RPM.

Glad I performed this engine swap myself. Well worth the cost savings and lesson learned of doing it myself...