Pre Alpha Outdrve slipped

[Sagabu]

I have a 79 Galaxie 17' V-hull w/120 Mercruiser (pre Alpha) . While out playing around yesterday , the freshly rebuilt outdrive (60 hrs)just quit driving outa the blue and all at once at 3800rpm. An odor similar to a burnt clutch (overheated brakes)was present . I brought it home and checked the gear oil and it seemed full and fine w/no metal shavings nor water, although it was black and smells like old oil but I assume this is normal. When cranking the engine a grinding sound is coming from the bellhousing area and gets much worse when the engine is fired and then comes and goes away . It will go in/out of gear but will not take the presure to move the boat . What is the best way to trouble shoot this problem so I can find the issue w/out dissasembling the complete unit .

 

[Alumarine]

Re: Pre Alpha Outdrve slipped

Sounds like the coupling between the engine and the drive is shot.<br />As for the oil, the correct oil should be a greeny/blue colour.

 

[Sagabu]

Re: Pre Alpha Outdrve slipped

Thanx for the quick response .<br /> I feel its better to ask before digging.<br /> Is there a link where I can find a schematic so I can know where exactly is it located and the easiest way to get to it, as well as a part # ? How can I test for its failure to pen point it w/out dissasembly ? <br /> Is the coupler you speak of the small driveshaft between the "U" Joints .<br /> What is the easiest way to get to it ?<br /> I have been feeling a vibration lately that I was assuming could be "U"Joints. <br /> Another fact that could play here , is an extra prop (15 pitch) was included w/the boat . When I switched from the 19 that was on it to the 15 for s&g, it did the same thing but only once . I swapped the props back immediately and put approx 50hrs w/no issues until now.<br /> Sorry to ask these questions , but Im primarily experienced w/jet boats and big blocks.<br /> The Mercruiser is new to me. I bought the Galaxie as a gift for my woman as she is not a speed demon like me. <br /> It has become our primary boat this year so I can restore my jet boats for next season. They are in peices and this is the only boat we have for the year.<br /> We are used to going out on the lake at least three times a week.<br /> I fear withdraw symptoms by the weekend.

 

[Sagabu]

Re: Pre Alpha Outdrve slipped

Ok ! I found the coupler and now understand its purpose. <br /> The burnt clutch smell and symptoms seem to point in that direction as the week link.<br /> Do the couplers have clutches internaly that are prone to failure?<br /> In researching , it seams that there are 4 different types of couplers(GM,Ford,tribolt,Bravo).<br /> According to my serial#5256852 Ill need part# 76850A2.<br /> Is it safe to assume that the easiest way to get to it, is to pull the engine and/or outdrive ??? I need pointers!!!<br /> Is there a simple test to confirm it is indeed the coupler before I pull it all apart?<br /> I had planned to restore and repower to a 260hp V-8 next year after my other boats where finished, making the Galaxie a classic sleeper w/power to spare. <br /> If I must pull it all apart to get to the coupler, I may head that direction.<br /> Any pointers or tricks for doing this job ?

 

[Alumarine]

Re: Pre Alpha Outdrve slipped

To replace the coupler you have to remove the drive unit first and then pull the engine.<br /> http://www.mercstuff.com/spunprop.htm

 

[Don S]

Re: Pre Alpha Outdrve slipped

Couplers are nothing more than the metal splines attached with rubber to the outer part of the coupler that is bolted to the flywheel. This in turn turns the outdrive input shaft anytime the engine is running.<br />The couplers are not "Prone" to failure, as long as they are lubricated with spline grease every year or 100 hours whichever comes first, and the alignment is ok. Obviously the alignment is way out on your engine, so I would suspect the rear motor mounts are bad also.<br />To check the inside of the coupler, just pull the drive and look inside.<br />Have a look at the link below.<br /><br /> http://www.marinemechanic.com/site/page79.html

 

[Sagabu]

Re: Pre Alpha Outdrve slipped

Thanx for the info guys . It is golden indeed.<br /> Today I put the outdrive in gear and spun the prop. Sure enough, the shaft going to the engine spun and I could feel the splines slipping by hand. The coupler is shot!<br /> Im sure that missalighnment was the cause as the engine and outdrive where rebuilt prior to my purchace of the boat. <br /> I contacted the previouse owner that had the outdrive rebuilt to see if she alighned the engine/gimble bearing before installing the drive. <br /> She (alternative life style)stated that she installed the outdrive and had no idea what I was talking about, so its safe to assume that it is not correct and the cause of malfunction.<br /> I started pulling measurments for the repower and am working a deal for a 260hp 350 complete to skeg including all mounts, trim, and through hull manifolds.<br /> The Galaxie should make a nice little sleeper and there is room for the smallblock.<br /> Ill be starting another thread for tips .<br /> Thanx,B.King