stripped driveshaft?

#1 03-16-2005, 07:09 PM

on what was to be the last striper trip of the year last season (dec), about 5 minutes from home, the engine jumped up rpm's and the prop stopped spinning. could no longer get outdrive into gear forward or reverse (no discernable click per usual when throttle is pushed). also, no bubbling out the prop, i.e. no water being circulated thru the engine, presumably due to shafts not spinning the impeller. started engine up today for first time since, runs fine, and next week i am going to pull the outdrive and see what's up, but am i probably looking at a stripped driveshaft where it couples with the engine? there is a whirring noise (like spinning without gears meshing) that gets louder with the rev of the engine, seems to be coming from right at the transom, on the outdrive side. any ideas on what i should look for when i take it off? how easy is it to put a new driveshaft/ujoint assembly in? any input appreciated.

oh yeah, and there were no signs of anything wrong up until the moment she wouldn't spin the prop anymore, and the prop does not have any damage, so i didn't hit anything.

oh yeah, '79 470, w/model 1 outdrive.

chumbucket · #2 03-16-2005, 07:14 PM

The outdrive is fairly easy to remove. Be sure the shifter is in gear before you remove it. It'll make it easier to pop the shift cable.
Before you do remove it though, are you sure you didn't spin the hub on the prop? I'd be checking that out first.

#3 03-16-2005, 07:55 PM

removing the outdrive i have done, i just haven't done anything except replace the impeller/water pump/bellows as a preventative measure when i bought the boat last year. would a spun hub cause the throttle not to click into gear, and no bubbles out the prop housing? i hope it's the hub, but would that make sense given the other symptoms? how would i check it? should the prop spin freely by hand or not? thanks for the help.

chumbucket · #4 03-16-2005, 07:57 PM

Probably best to have a prop shop check it out. Sometimes they feel okay, but slip when under a load.

macojoe · #5 03-16-2005, 09:59 PM

I bet that the drive shaft is good!! More then likely you blew the engine coupler!!
Been there done this!! If I am right?? you are going to have to pull the engine!!
How I did this was I layed a piece of ply on the deck, then I rented a engine hoist and put it right in the boat.
Jacked the motor right up and pushed the hole hoist forward. Now you are able to work on the motor right there.
you will have to remove the bell housing to reveal the coupler. Just unbolt it like a fly wheel on a transmission.
Replace the coupler and do it all in reverse.

Now there is 2 things about this. if you unbolt the motor from the mounts, you will have to make sure that you get it straight when you get the motor in!! So that the out drive is aliened with the motor!!

You can avoid this if you unmount the engine mounts from the bilge and not mess with the motor side of the mounts. This way it only goes in one way and the alignment will stay good .
But sometimes the holes in the bildge will be rotted and they will not take the bolt when you try to reinstall. Then you will have to fix that.

Ok anough for now!!

macojoe · #6 03-16-2005, 10:01 PM

I have a Steel Bracket for sale in the for sale thread!! ;D

#7 03-16-2005, 10:05 PM

If it is a merc cruiser there is a coupler on the back of the engine it is round with rubber in the middle that the shaft goes through so when you put the engine in gear it has some has give it is hard to explain if you have the book on this engine look it up i am sure thats what's wrong if it is a merc. inboard/outboard did it smell like rubber burning when it happened that is what it is

macojoe · #8 03-17-2005, 12:05 PM

Thats the engin coupler. It will not always smell like rubber. Mine the teeth got striped.

If it was the drive shaft you would here it banging around in there!!

While you have it apart ck all the bellows houses and water pump. You might as well get it all done at once so you don't have to play with anything during the fishing season.

You will also have to get a outdrive install kit. It has a new gasket and O ring for the water jacket.

It is a lot of work but if you set your self up right and ahead of time you should be able to get the motor out, fixed, and back in with a couple of buddies in about 2 to 3 hours.
I was set and had it done with some help from a couple of friends in just about 3 hours.
Thats the motor part, then you will have to reinstall the out drive. Reason I mention the time is that I rented the engin hoist for 4 hours at a cost of $15

Good Luck!!

jaysea · #9 03-17-2005, 12:33 PM

in talking about your in put shaft an coupling on my i/o you con see the shaft for the out drive going into the back of the motor ,you mite check to see if its turning before you start to pull that engine ,good luck

#10 03-18-2005, 01:50 AM

thanks for all the help. i definitely had it in my mind to make sure it's not the input shaftamabobby, since i've never pulled an engine before, i remember putting the outdrive on at the beginning of last year and thinking the teeth didn't look perfect. why would it definitely be the coupler and not the input shaft thingy? any idea what it should cost to have a marina do the work, parts and labor, if it is the coupler?