25 hp johnson question

[jim2late]

I have a 1971 25 HP johnson with electric start that starts and runs great... however when you take off and start to pick up speed at about 1/2 throttle it acts like it jumps out of gear and the engine rev's up... you can back off on the throttle and it reengages and you can proceed... it runs fine at 1/2 throttle but when you speed up from there it acts up... ANY HELP APPRECIATED.... thanks

 

[Boatist]

Re: 25 hp johnson question

Jim<br />Sounds like a spun prop to me. Take prop nut off and with a magic marker mark from the inside hub acrrosed the rubber to the outside hub. Go for a test run and then check to see if mark still lined up. If it is a spun hub it will not be ligned up. Also can sometimes see deformed or melted rubber around hub.

 

[G DANE]

Re: 25 hp johnson question

Hi jim2late<br /><br />Unfortunetely the 71 25HP do not have rubberhub.<br /><br />It is most likely the clutchdog in lower unit that is worn, perhaps the forwardgear too.<br /><br />Get a manual - and on these horisontaly split geacases you should be able to change it yourselves, if you have some mechanical skills.<br /><br />A new clutchdog is around 50$, available at most dealers.

 

[cecil1974]

Re: 25 hp johnson question

most likely the prop mine done the same thing to me last year i fish river so i have had some prop problems it will only get worse till you get a different prop for it clutch dog probably wont be far behind it mine is going out as we speak good luck with it

 

[tx1961whaler]

Re: 25 hp johnson question

spun prop....clutch dog is usually described as "banging" or "hitting a log"