73 merc 200 (20 hp) Prop slipping

[Scotty Van]

I hope that it's only the prop slipping. I was out with my son today and we were cruising around and the motor was fine. We were bogged down a little in a weedy area where I had to pull weeds off the prop a few times but the power was ok just bogging down. After getting to clear water, I cleaned the prop and lower unit/cavitation plate of all loose weed and we got on plane at WOT. About 10-15 minutes later-the prop would not let loose and we had no bite in the water. The engine seems to run ok but the prop will only push the boat in gear at idle or a few rpm's above that. Reverse seems better but it was pretty rough and I didn't really want the boat to fill up with the waves that were coming over the stern.<br />14' smokercraft not over loaded with gear or people and we have been in a similar configuration all summer with no problems at WOT.<br />Pulled the prop off when we got home and found only some fishing line tangled on the hub and some distortion of the rubber which is in the prop housing itself where it meets the spindle shaft. <br /><br />Suggestions and keep the bad news to a minimum please.

 

[corm]

Re: 73 merc 200 (20 hp) Prop slipping

Hi,<br />Send the prop up to North American Propeller in Schofield Wi.(by Wausau) and get it rebuilt. Or buy a new one.

 

[Scotty Van]

Re: 73 merc 200 (20 hp) Prop slipping

thanks Corm<br /><br />Can't get out of town with all these harleys in my way!<br /><br />riley

 

[corm]

Re: 73 merc 200 (20 hp) Prop slipping

wOOt, woOOoT, it's a big party down there.<br />They should have a Harley cam like in Sturgis.<br />mmmmm.....maybe they do. I'd better check. I know there are no Harleys left in town here today.

 

[greasemonkeyozi]

Re: 73 merc 200 (20 hp) Prop slipping

Yeah your prop's sheered bro. Happens all the time, its like getting a flat tire for a boat. Rather sheer a $100.00 prop than a $1,000.00 shaft.

 

[Merc90HPnewbie]

Re: 73 merc 200 (20 hp) Prop slipping

Holy crap! I had EXACTLY the same experience today word for word. Except for the rubber, I don't think I can see that. Got some weeds on it prop, a bit of fishing line on the prop, and nothing else went wrong today, Boat had 3 people on it and is rated for 6. Do all props have an internal rubber hub? What causes the hub to go south?<br />Thanks!

 

[greasemonkeyozi]

Re: 73 merc 200 (20 hp) Prop slipping

I have noticed that most of merc's props have rubber sheer mechinisms. As ya know, in time rubber will dryrott, especially in water. Dryrott + torque + a little heat from exaust = a sheered prop.<br /> I havnt looked at a stainless steel prop cause they are so expensive, I dont know how those sheering mechinism works, but I do know that mercury has come out with a new kind of black inexpensive prop that doesnt sheer as easy. I had bought one for $50.00 new, and looking at it, I noticed that the rubber inside it is alot thinner. Looks alot stronger.

 

[Scotty Van]

Re: 73 merc 200 (20 hp) Prop slipping

So do we fix it for $35 or so or buy a new prop or fix it AND buy a new prop so there is a backup?<br /><br />It is a 3 blade prop with the letters A4L 9P stamped on it.

 

[corm]

Re: 73 merc 200 (20 hp) Prop slipping

Hi,<br />I am a big fan of the extra prop. Not because I sell them but because I don't like to go home early from the lake. In my little boats I leave it in the trunk, big ones it is always with me with a wrench too. I have an extra thrust hub and nut too. I hate going home. Well till I want to anyway. On the other hand the last one lasted for yrs as the new hub should too.