Mercruiser Stern Drive Repair or Replace

[Island prospector]

I purchased a new Mercruiser Alpha 1 Gen 2 leg in Nov 2010. It was broken in properly but in hindsight exhibited a variable intermittent harmonic buzzing noise that at the time was thought to be due to break-in or propeller noise or just general engine noise and could not be isolated. I run an aluminum propeller which has signs of cavitation burns. This noise was not always noticeable. The leg oil was changed after break-in at 20 hours and looked OK and the magnetic plug had some iron fuzz on it. Over time the noise has however increased till now it is more or less continuous generally over 2500 rpm. This noise was thought to be due to the gimbal bearing which was changed at about 100 hours of time on the new leg but without stopping the noise. The propeller was also changed without any change or reduction of noise. The oil was changed again at about 90 hours by a reputable boat repair company. The oil was dark but still green. The magnetic plug showed evidence of iron filings (fuzz) but this was not considered significant at the time and was attributed to grinding gears due to shifting too slow. The leg now has about 118 hours on it. The oil was checked and found to be quite dark and smelled burned after the last 28 hours of operation and there is quite a bit of metal, still fuzz, on the magnetic plug. We now suspect a bearing is going probably in the lower drive line as the noise does not appear evident when not in drive. This has probably been going on since new but the one year Merc Warranty will not help us out as we are past 2 years. In hindsight we probably did not pay enough attention to the iron on the mag plug. My question is before even spending money on disassembling, is it worth repairing or should I just replace the lower leg or the whole outdrive since there has probably been some fine metal floating through the system for some time now?

 

[achris]

Re: Mercruiser Stern Drive Repair or Replace

Hello and welcome to iBoats...

Interesting problem. Just because the noise is only evident in gear does not mean it's in the lower housing. It may only manifest when load is on. I had a drive just recently with the same thing, noisy but only when in gear. It was the top bearings, all water damaged. I replaced those and the noise is completely gone... so...

I guess the question becomes, how are you mechanically, and are you willing to have a good at this? Another part of the equation is.... New SEI drive is $1300. Just to strip and assess your drive will be about 4 or 5 hours labour (that's upper and lower housing)... If you decide to commit to a new drive, then you have nothing to lose by pulling this drive apart. So... What tools do you need?

I would get just a couple of special tools now. I would get the snapper for removing the cover nut on the front of the upper housing, as standard hand tools will take it apart the rest of the way. The lower housing is a little more complex to strip. You need to remove the cover nut (behind the propeller). That can be done either with the special tool, or as most of us do with older drives, just drill the nut and break it out... But you'll need the tools to tighten the new cover.

The choice is yours (I guess you already knew that)... I would at least remove the top cover from the drive and look at the condition of the top bearing. If that's looking water or lack of oil damaged, then it might be worth just re-bearing the upper housing....

HTH,

Chris.........

 

[Island prospector]

Re: Mercruiser Stern Drive Repair or Replace

Hello and welcome to iBoats...

Interesting problem. Just because the noise is only evident in gear does not mean it's in the lower housing. It may only manifest when load is on. I had a drive just recently with the same thing, noisy but only when in gear. It was the top bearings, all water damaged. I replaced those and the noise is completely gone... so...

I guess the question becomes, how are you mechanically, and are you willing to have a good at this? Another part of the equation is.... New SEI drive is $1300. Just to strip and assess your drive will be about 4 or 5 hours labour (that's upper and lower housing)... If you decide to commit to a new drive, then you have nothing to lose by pulling this drive apart. So... What tools do you need?

I would get just a couple of special tools now. I would get the snapper for removing the cover nut on the front of the upper housing, as standard hand tools will take it apart the rest of the way. The lower housing is a little more complex to strip. You need to remove the cover nut (behind the propeller). That can be done either with the special tool, or as most of us do with older drives, just drill the nut and break it out... But you'll need the tools to tighten the new cover.

The choice is yours (I guess you already knew that)... I would at least remove the top cover from the drive and look at the condition of the top bearing. If that's looking water or lack of oil damaged, then it might be worth just re-bearing the upper housing....

HTH,

Chris.........

Hi Chris Thanks for the feedback.
Yes I am thinking about stripping it down myself to check out. However what is your thought about the potential damage of having cuttings floating around the system? Is that a major concern for rebuilding? And of course I am also wondering about going to an SEI drive because of the cost as you note. Do you or anyone else have experience with courier delivery of SEI products to Canada, customs etc? However I have just gotten a quote from my local boat shop for an new Merc drive for $2975 CAN before taxes which makes it pretty competitive as well.

 

[britisher]

Re: Mercruiser Stern Drive Repair or Replace

A brand new SEI Alpha 1 Gen 11 sterndrive is $1475 US ($1575 CAN) on their website (shopsei. net). You would have to contact SEI to find out shipping costs, etc, but that's $1400 CAN cheaper than the $2975 CAN Merc drive. The SEI warranty is 3 years fault free, what is the Merc drive?

 

[SWD]

Re: Mercruiser Stern Drive Repair or Replace

Courier brokerage fees can be very pricy. Best to pick it up yourself or at least get it sent to close to the border then pick it up. You'll only have the GST to pay, unless its made off-shore, then you may have to pay some duty on it. If you rebuild, I would use loads of varsol and air to clean it all out before re-assembling it.

 

[mercs4mark]

Re: Mercruiser Stern Drive Repair or Replace

I think I would look at the top bearing for wear, change the fluid more frequent, and run it. Fuzz on the drain plug magnet is normal in my opinion.

 

[achris]

Re: Mercruiser Stern Drive Repair or Replace

Hi Chris Thanks for the feedback.
Yes I am thinking about stripping it down myself to check out. However what is your thought about the potential damage of having cuttings floating around the system? Is that a major concern for rebuilding? And of course I am also wondering about going to an SEI drive because of the cost as you note. Do you or anyone else have experience with courier delivery of SEI products to Canada, customs etc? However I have just gotten a quote from my local boat shop for an new Merc drive for $2975 CAN before taxes which makes it pretty competitive as well.

???? Have a look at my location... (just under my name and avatar over on the left)....