SeeVeeZ1972

I would like to know if anyone has re-powered a 31 contender with twin Suzuki DF300B engines. The boat in question is a 1999 and my concern is if there will be any issue with the weight of those engines with this particular boat. According to Suzuki’s website, the DF300B weighs 745 lbs

kmoose

That is a lot of weight on the back with those so I would opt for the DF300AP instead of the duo prop only due to weight. I am familiar with that hull and the df300aps will fly it. For the record, Suzuki has provided me with excellent service for over 15 years of ownership with multiple 4s outboards.

Sandpiper John

If weight is a concern did you look at the V8 Mercury? I think it's much lighter and from all the reports it looks like it's the most economical with the most torque.

SeeVeeZ1972

I already have the DF300B’s. What are the big concerns with this amount of weight, is it that the transom might have trouble supporting it or the location of the scupper valves?

Texas 17

Completely agree with this. I would not want the extra 300 pounds on the back, plus the DF300AP is a proven platform. The duoprop might mitigate some of the weight issues as it seems to produce more stern lift, but I would not want to be the guinea pig with so many proven options available.


edit: I was typing when you were typing I guess. If you already had the motors, I guess there is not a ton to lose trying them. My limited experience running that boat is it was really light in the bow. With that much extra weight on the transom, my guess is you'll end up disliking the rough water performance especially when the livewells are full. Maybe not... but I suspect you are going to find the bow getting tossed around more than is comfortable, and more than allows the hull to really function at it's best.

leoaa777

You might have to throw some weight on the bow.

SeeVeeZ1972

Thank you all for your input.

SeeVeeZ1972

Yes that’s probably what I’ll end up doing if I am having issues

kmoose

You are right that under way the Bs would make up for their weight as the 350s definitely can keep the bow down over single props on larger hulls. My big concern would be at rest. Those hulls were engineered for v6 2 strokes and handled wonderfully. I guess the OP could add the static weight difference plus a few guys in the back to see how it feels with his current set up.

kmoose

That's not a bad plan. That hull rides better when it's heavy anyway.

captbone

I would not consider the Duoprop 300hp Suzuki's at this time due to the documented issues with the gearcases and powerheads. Several cases have been reported on the THT which then lead me to seek out and ask any owner that I see with the 350hp Suzuki if they have had any issues and if they like them. The feedback has been less then stellar as far as parts availability, supply chain issues and issue with water in the gearcase and powerhead issues above 500hours.

My reply like everything else on the internet is unsubstantiated and speculation which ultimately is just opinion but I offer my advice as a warning to dig a little deeper before pulling the trigger on the Duoprop 300hp Suzukis. The standard 300hp Suzuki has a good reputation as does the Yamaha and Mercury in the 300hp range.

SeeVeeZ1972

Good to know, thank you for the input.

Scott D

Not sure on the Contender 31 and how it will handle the extra weight. I have a GW 300 Marlin and went from DF300AP to DF300B motors and the boat is faster and more economical with the 300B's but the biggest positive is the grip that you get with the contra rotating props. You can plane the boat at a very low RPM (I think its about 3200) and it feels like it is on rails. In rough water it will not ventilate. Very good throttle control and no prop slip whatsoever. Having owned a bunch of 300AP's and now 300B's the 300B is a much better match to the GW which is a very heavy boat. The boat does not notice the extra weight of the 300Bs at all but again the Contender may be different.
I think many of the issues with the 350's were form the first year of production and those issues have been addressed. The 300B's came out a year later and already had the updated parts.

Shift Work

Why not go for the 350’s if your going dual prop? There’s a 31 open that sold about 6 months ago with the dual prop 350’s on it. The guy said he was getting close to 2mpg at 40 and 60 on the pins

Scott D

My boat is rated at 600hp and I didn’t want to exceed that rating. But otherwise I agree more power is better!