Cummins/Stern Powr problems
Hi guys, I've got a friend with a locally (Kauai) made 24' boat (Radon type; heavy ply-glass construction, built like a tank;for the most part it's rough here) with a single 210 hp Cummins diesel coupled to a Stern Powr outdrive via a Borg Warner transmission; this trans/drive has been giving out consistently over the past couple years. He gets a couple trips out of the boat, then breakage. Clearly, the 10,000 lb. boat is too much for the mechanicals (model 1000 Stern Powr).
1. Do any of you mechanical types know if there's a way to couple this motor to a different brand of outdrive (that may be able to handle the boat)? A new Stern Powr drive costs 18k from Maine. The diesel runs excellent. Adapters for Volvo?????
2. He's considering ditching the I/O in favor of closing the transom hole, adding a aftermarket transom extension and going with twin Yamaha 4 stroke outboards; looking for 200-250 long shaft, controls, steering. Any ideas where to find a used set?
3. He's also considering swapping out the current package with a used Volvo D-6 with a DPH or something Volvo outdrive (not sure the model designation). He can get a 1200 hour complete package (single) for about 22K.
4. I favor #2 because single power here is not a great idea; often he takes multiple day fishing trips to Kaula rock (56 miles from Kauai, across the channel which can be crappy).
Konrad makes a heaver duty drive that you can replace the out drive with. another solution is going to an arneson surface drives . There is no easy solution. The new Volvo D-6 is rated at over 370 hp my guess is the cost is $38000 plus installation. You might check boat diesel .com it is a good place to look for answers. If the boat would take it twin out boards on a bracket could work. Would be cheaper that installing a diesel and new drive.
Unfortunately, problems with diesels chewing up outdrives is nothing new. I own my share of junk drives. I don't know much about Stern Power units, but I'd imagine the problems are the same as the others. Basically, heavy boat + high torque diesels= broken drive. Alignment issues and vibration issues also tend to aide in the destruction of drives.
Some ways to help the situation are to drop a size or two in prop pitch and to really baby the boat (bring it up on step easily, no fast throttle punches, jumping waves, etc.). In order to reduce gear "chattering", I also always idle up to at least 1000rpm while in neutral or moving around the harbor.
I think it really depends on the situation, but if the package is right on the edge of working, reducing the prop pitch may make a world of difference.
As far as heavy duty drives go, Merc Bravo 2X (the stoutest stock drive), BMAX, and IMCO, are drives that work without transmissions. Konrads are heavy duty, but require transmissions behind the engine.
I guess I missed that you have a transmission. As dd says.