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I'm nearing the completion of my 25 restoration. So far I've replace both cabin bulkheads, fuel tank floor, new transom core and paint. The original plan was to go back with new 3.0 I/o's, new gimbal brackets and drives. The boat handled wonderfully with this combo. I never really felt it lacked all that much for power and the fuel economy was pretty good. However, since tearing the boat apart the prices for the motor drive combos have gone up almost 3k a side. The cost of outboards at this point are not considerably higher.( I have a friend in the business). Just would like to get thoughts from those of you who have run the boat both ways. I don't particularly care for the look of outboards on a classic Bertram but the thought of never having to change manifolds,risers, bellows........... Etc. etc. is pretty appealing. I however do not want to hurt the ride quality or low speed handling of the boat. Any thoughts are appreciated. I'll try to add some pics to the thread soon

Hi,

I had my boat setup with twin !/Os for over a decade and ran them till I couldn't stand fixing them anymore. I have a moppie that I turned into a center console, with the twin I/Os I got 22-23kts at 3600RPM and guessing 10-11GPH at cruise. I could top out at 34kts. I was under propped with 15x17 and could easily over rev the motors, I probably should have had 14.5x19 or 14.5 x20 props.

The big thing for me was fixing the motors, I couldn't get more than 3 or 4 trips without fixing something. I finally tapped out.

I now have a single 300 suzuki and absolutely love it. I cruise at 25kts at 4050 rpm at 10.25gph at 4300 rpm 27kts at 13gph, and 4500 29kts at 15gph. She'll top out at 40kts.


I was worried about loosing slower cruising speeds as I was loosing a lot of properller blade area and I did loose some, there is a hole between 2500rpm and 3000 as she gets a bit inneficient but most of the time I just accellerate through it and don't notice.

I appreciate the reply. If I go outboards, I will definitely be going twins. Somewhere in the 140 - 200hp range. Looking for max efficiency and reliability. There are some pretty remote Bahamas runs in store for this boat once she is completed.

From my experience the ride and balance is better with transom mounted vs. bracketed outboards. I am biased since that is the direction I took but I spent hundreds of hours researching the conversion of 25 Bertrams to outboards.

Based on your information, I would go with twin 200s and carry spare props. With the proper low pitch propeller, you can easily plane off a 25 Bertram with a single 200hp outboard and cruise at 25mph.

Anyone have any thoughts on a pair of Suzuki 140's. I have a buddy that's about to sell a low hour pair. Ive seen a couple boats with 115's on them. Should be enough power.

Hi Brian,

this is probably internet hogwash but I have always heard that the suzuki 140 was the same block as the 115 and it was tweaked out to get more HP. I've also heard that they don't make the rated HP.

on the other hand, most of the different brand 150s seem to make 150 or better.

I have no experience with any of these except a merc 150 four stroke where a buddy repowered a seacraft 20 from a 150 yammie 2 stroke to a merc 150 four stroke. he lost 1-2 mph top end and a bit of accelleration and some extra weight in transom but fuel burn was quite a bit better.

How much does the 25 boat weigh?

You are reminding me that I need to run over to my friend's Sea Ray and help him install new pulleys, belt, exhaust flappers, etc. on his merc 350 Mag, Bravo 3...hopefully that fixes it, but it's an I/O, so you never know. He is on a first name basis with Sea Tow.

Outboards, baby. None of that crap to deal with. 1 is plenty for a 25, 2 might be a bit more balanced, but at 45 mph I don't notice it...I'm just hanging on!

CamB25 wrote: ↑Jun 26th, '24, 14:55 He is on a first name basis with Sea Tow

I understand about that.

My first two seasons with my 31, the guys from Sea Tow knew where my slip was. Five years later, though, I still love my 454s

It takes time to learn the boat, motors and their idiosyncrasies. It takes time to fix what should have been taken care of a long time ago.
It takes time to learn the sounds that tell you I should not think of going out till I take care of that. Stuff like a bad cranking motor...battery? Starter? Water in cylinder...ugh. Squeaky crunching of a water pump going South. Exhaust note a bit louder telling you that the Raw Water motor is not pumping enough water...maybe something simple like a new impeller, cam, wearplate or maybe loose belt or ugh Risers. Those little tips that you learn to deal with and take care of before going out and needing to call SeaTow for a ride back.