New or Refurbished Sterndrive

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dsabey

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Hello. I was hoping to get some advice on what to do with a RIB that needs a replacement sterndrive.

I have a Redbay 6.1M RIB which blew a piston a couple of years ago. The engine is a Mercruiser 1.7D 120HP.

While the engine was getting refurbished (replaced all 4 pistons, injectors, etc) the sterndrive was damaged beyond repair in a fire. Fortunately it was not attached to the boat at the time.

The engine is close to completion now and I am considering what to do with the sterndrive. It's a Mercruiser Alpha One Gen 2.

The boat itself was built around 1994 and the hull and tubes are in very good condition. I paid £15k for it around 4 years ago.

The decision is how much to spend on the sterndrive. Would it be a good investment to buy new (£3k) and would that help the resale value in say a couple of years. Or should I find something second hand (I believe I can find something <£k) that would do the job just as well as long as it lasts....

I'm hoping the boat has not depreciated too much and a new sterndrive would help keep its resale at or maybe even above what I paid for the boat in the first place.

Any thoughts?
 
Just buy new at those prices and enjoy your boat. Seriously, been there and done that with an Alpha 1 MR. I'd be more circumspect with the bigger outdrives but there comes a point as in your case the labour time and effort in reconditioning an old drive no longer makes economic sence and diving down that rabbit hole just not worth it. Will it add value to your boat, no. But it will add value to your enjoyment and peace of mind and will make the boat a more desirable sell if maintenance and service records are kept and any warranty handed over.
 
Blown piston on a 1.7dti? Was a seized wastegate the cause and if so, was it fixed? I did some research into these engines a few years back and they frightened me a bit. Good as they are they have a poor rep. for the above.

Genuine question, would you be better off selling the engine and putting an outboard on the boat? Be more reliable, less to service and you’d have more space. Refuelling can be tricky but only you can answer that. It’s probably a more expensive proposal but you’ve missed enough time. 6.1 is a great boat btw. Drove one once and found it to be an excellent seaboat.
 
That outdrive will be no doubt able to be refurbished. Might be hard to pick up a used one, given the ratio in those, being mated to the diesel. Haven’t looked into it. For the price of a refurb, you’re not too far off a new one really. Don’t be tempted by the after market drives. They aren’t up to much to be honest.
 
Definitely go for new as even if its refurbed its still an old drive with some new parts in it. And check the turbo wastegate isn’t seized, this is a service item item but not all workshops lube the shaft where it goes into the turbo so if its not used for some time they seize and then it takes out the pistons.
 
Thanks everyone for the comments and advice - this really helps.

I have also been quoted £1595 for the "aftermarket" SEI sterndrive by a company in Poole. I wasn't sure how it would work with spares, etc.

Cheapest option is this one on eBay which seems to work but I'm wary of fitting something that is older than the boat itself.

mercruiser alpha 1 gen 2 Complete Drive | eBay
 
Ferris said:
Blown piston on a 1.7dti? Was a seized wastegate the cause and if so, was it fixed? I did some research into these engines a few years back and they frightened me a bit. Good as they are they have a poor rep. for the above.

Genuine question, would you be better off selling the engine and putting an outboard on the boat? Be more reliable, less to service and you’d have more space. Refuelling can be tricky but only you can answer that. It’s probably a more expensive proposal but you’ve missed enough time. 6.1 is a great boat btw. Drove one once and found it to be an excellent seaboat.
Click to expand...

I read about the waste gate issues on some forums too. The mechanic told me the waste gate had been removed so couldn't be the issue . It was piston number 4 that went - not sure if that tells anything more?

Next step apparently is to test the injectors to see if one of them was at fault. I'm not mechanically minded so following instructions on this really...
 
spannerman said:
Definitely go for new as even if its refurbed its still an old drive with some new parts in it. And check the turbo wastegate isn’t seized, this is a service item item but not all workshops lube the shaft where it goes into the turbo so if its not used for some time they seize and then it takes out the pistons.
Click to expand...

can anyone explain what the purpose of the waste gate is, and what the implications of removing it are? Does it matter that all the exhaust vents directly onto the turbo? Or am I misunderstanding how it works?
 
A wastegate is a valve that controls the flow of exhaust gases to the turbine wheel in a turbocharged engine system. ... The primary function of the wastegate is to regulate the maximum boost pressure in turbocharger systems, to protect the engine and the turbocharger.
Click to expand...

To make the turbo efficient at the widest rpm range and avoid lack (while the turbo spools up in rpm), it is designed to build boost as early as possible at engine rpm. Hence, when engine rpm approaches max. the exhaust driving the turbo has to be controlled, ie. 'wasting' the boost by letting it out instead of into the engine .
Disabling or removing boost control on engines that are designed with it, most likely will kill it. Fast.


The base engine for the Mercuiser 1.7D originally (1992?) was an Isuzu, later taken over by GM and used in cars, under 1.7 DI, 1.7 DTI and 1.7 CDTI badges.
Introduced by Merc in 2003, updated regularly for car use but there are many complaints from boat owners, mainly regarding performance and breaking when run hard, which marine engines tend to be.

Due dilligence and timely service/maintenance is key but no guarantee :cautious:
 
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Thanks for that chromdome. So without a wastegate at high revs are the exhaust gases exerting pressure back onto the cylinders as well as the turbo wheel?
 
None of the KAD engines have a wastegate neither D4 or D6, only the larger engines have wastegates. The D3 has a variable nozzle turbine VNT which needs checking for free movement when servicing.
 
The KAD had a supercharger so low speed boost was covered, therefore they could set the turbo to boost at higher revs and they could control the boost that way
 
The first Volvo 3,6 ltr. I encountered was in 1980, in a Volvo F4 truck. Some 100 hp at 4000 rpm and so gutless, there was a competition among the company drivers about who, if any, would get a speeding ticket. Fully laden the top speed was well within city speed limits, even if standing on the pedal all day long.
I don't remember anybody ever getting near..

Over time, by tweaking, fiddling, adding compressors and turbos plus electronic engine management, they got the performance up.

Memory however prevented me from ever wanting any of these lumps or their successors..
 
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