View Full Version : Motor revs out?

28-07-2002, 09:37 PM
Just a quick one, I'm new to this motor repair stuff but I have had a problem today with my 70hp merc and would like to have a crack fixing it. Basically it will rev normally and cruise up to about 6 knots, when I put the throttle down it revs out on the spot and loses all drive and I go nowhere. Any thoughts regarding the problem and ease (or lack thereof) of fixing it myself would be appreciated. Thanks .

29-07-2002, 05:11 AM
sounds like a prop problem !

Kerry will know.

29-07-2002, 05:31 AM
Sounds like a prop problem too. I'd be checking if the hub has spun. If the hub has spun it can be fixed but it's not really something you can fix yourself without the right gear.

Cheers, Kerry.

29-07-2002, 08:15 AM
Thanks for the sugestion, someone suggested I -

"Put motor in gear,switch off, and see if you can turn the prop without the powerhead trying to turn."

I've done this and the prop will spin without the powerhead turning (reverse seems to be ok),there's a clicking sound as I turn it. Also the spline in the middle of the prop is spinning as well when i turn it,so I don't think it is the hub. My prop has actually been stuck on now for several months, I was going to run it out and then have it ripped or oxy'd off. Do you think it is something inside the lower unit that has given up?

29-07-2002, 11:26 AM
I had a 150 merc that did the same thing once..it only happened once as i was coming over the tweed bar..i picked up some heavy line it chewed out the the rubber centre of the prop my lower seal and chewed out the spindle on the lower drive shaft what a job..The mech was good got it apart with heat had to cold weld the shaft was expensive but did the job, hope its not as bad as that.

29-07-2002, 04:02 PM
So if given all available throttle in reverse does the same thing occur ???

If not then is the control box/cable adjusted properly to ensure it's going fully into gear ???

Props should be removed regular and inspected for things like spinning hubs as well as making sure the prop will come off when one really needs to remove it.

Also the hub and the prop proper can be timed to checked if the hub is overly spinning (there can be some slight movement under normal conditions), which is normally evident if one knows what to look for.

Cheers, Kerry.

31-07-2002, 10:15 AM
You were spot on fellas, I had a rooted bush on the prop...$80 for repair, including having the stuck prop removed... thanks for the tips, you never stop learnin...back on the water this weekend!