110 johnson max rpm

[claude75087]

i just bought a boat with 1986 johnson 110 hp and was wondering what the max rpm should be. with the prop that came with it i get about 5050 rpms. there was not any paperwork that came with motor and can't find anything on the net. any help would be great

 

[emdsapmgr]

Re: 110 johnson max rpm

The factory recommended 4500 to 5500 back in the day. Current thinking is that you should prop the engine to max out at the upper limit, or 5500. If you are only getting 5050, you are "lugging" the engine-slightly. If you drop to the next prop size lower, you will pickup 300 rpm, and much better holeshot. Your overall operating fuel economy should improve very slightly. You may even pickup a mph or two. That engine is considered at high perf model and should still make good hp up to 5700+ without any problems.

 

[hidef]

Re: 110 johnson max rpm

Your Max RPM operating range is 4500 to 5500 with your engine making 110 horse at 5000 RPM. So you are in the ball park although I would decrease your prop pitch by 2" to get your RPM up to 5300 or so. The smaller prop will give you a better hole shot and would be better for hauling water skiers. You can buy a service manual and an owners manual at

http://www.marineengine.com/parts/parts.php#manuals

 

[claude75087]

Re: 110 johnson max rpm

looks like i need a 17inch prop as l i am using a 19 now. i have an aluminum 17 inch prop but it is junk. thanks for the info

 

[emdsapmgr]

Re: 110 johnson max rpm

Your thinking is headed in the right direction.