Yamaha F-250s...... Repower?

Gary M · Aug 18, 2019

Looks like I'm going to repower the old 2001 Marlin with Yammie F-250s. I will hope to use the old, mechanical throttles, etc for cost purposes.

What are the pros of the F-250s?

What are the cons?

What about props? I don't care about speed/acceleration but more concerned with fuel economy at cruise as I plan to resume my summer trips over to the Bahamas.

For the older boat, will I find any 'rot' in the transom when the engines come off?

What else should I think about having done during this process? New fuel lines? All the way from the tanks?

Much thanks in advance!!

seasick · Aug 18, 2019

What was the power before? I can't comment on the pros or cons without knowing how it was powered originally.
What F-250s are you looking to fit (model year, counter rotating ...). .
I am sure there is a lot to think of and fuel lines may be one but they should have been looked at all along. If there is ant doubt, change the hoses.
Check the steering components also, brackets, rams etc.
With the motors off, you should inspect and address any issues with the transom, especially the cap if there is one and the mounting holes which may need to be resealed.
I would definitely go for new control cables unless you have already changed them in the last couple of years and don't currently have problems with them.

Ky Grady · Aug 18, 2019

Looks like from his signature, he is running the OX-66 250's.

Are you going new 4.2 F250's or old school 3.3 F250's? I have a friend, member on here, that went to the new 4.2 and seems to like it very well. He repowered from a 3.3 250. Seems the only issue is you need to do a hard break-in to seat the rings, after that you're golden. The F250 seems to be the backbone of the bigger Yamaha's, then the 300's and so far, the 425's are doing well, not that there are a lot of them out there yet. On the older Marlin, the 4.2 F250's would be a great package. A little bit lighter than the 3.3, better fuel burn and more torque, what's not to like?

Legend · Aug 19, 2019

I went from 3.3 F225s to 4.2 F250s with mechanical controls 2 years ago. I never had an issue with the 3.3s until the infamous corrosion issue got me. As good as the 3.3 are the 4.2 are even better. I have more HP but the mid range torque and top end speed are significantly improved. I have seen a slight improvement on fuel too. You should see a significant improvement with fuel over the older models. One thing I regret doing when the engines were off was to replace the aluminum transom cap with a glass over or the new plastic caps. I just noticed that I have one of the screws on my has pulled through and will have to deal with that eventually.
Props on my Sailfish SWS 15 1/2 x 17. These are perfect for the SF and get me close to 5.9 RPMs, Not sure if the Marlin would run different size.

Papa J · Aug 19, 2019

I went from twin OX66 225 to twin 2006 F250. Found a set on the east coast for a good price. Put them on a 1998 272 Sailfish. Boat runs great 40+kts when it's flat. Cruise about 26 kts 3800 rpm @ 1.6mpg.

SmokyMtnGrady · Aug 19, 2019

Ky Grady said:
Looks like from his signature, he is running the OX-66 250's.

Are you going new 4.2 F250's or old school 3.3 F250's? I have a friend, member on here, that went to the new 4.2 and seems to like it very well. He repowered from a 3.3 250. Seems the only issue is you need to do a hard break-in to seat the rings, after that you're golden. The F250 seems to be the backbone of the bigger Yamaha's, then the 300's and so far, the 425's are doing well, not that there are a lot of them out there yet. On the older Marlin, the 4.2 F250's would be a great package. A little bit lighter than the 3.3, better fuel burn and more torque, what's not to like?

Yeah, I know that guy you mentioned that did that from the 3.3 to 4.2. if you can swing it, go digital. Yamaha seems to have hit and misses on their big block motors. The 300 4.2 liter powerhead is proven to be a hit. The low end and midrange torque of the 4.2 is nice and honestly I like the sound of the motor especially around 4200 to 4800 RPM it just has this smooth purr to it.

Gary M · Aug 20, 2019

Thanks for the Replies.

They are 2001 OX-66s and getting tired. Boat is limited to 500HP hence no 300s.

I will use the IRAN method for this job. Inspect and Replace As Necessary. From the top of the throttles to the props.

Batts, cables and new key switches are 2 years old. New-er steering cables with zero problems there.

I'll look at Digital but won't spend money there unless it makes economic sense. I still need new canvas and probably a new genset.

Back to the Bahamas next summer hopefully!

brdawg2001 · Aug 20, 2019

I would consider Zukes...I did it and am very happy...very...

Tuna Man · Aug 20, 2019

I've got old school 2006 F250's on our 2006 Marlin. Very happy with them overall. My son and I were speaking about it today, we have never had an alarm go off since we owned the boat (bought it used in February 2008). If we can afford it we will re-power with Yamaha or Suzuki 300 outboards someday. While our F250s are certainty adequate, it would be nice to have and extra 100hp when fully loaded for a canyon trip.

Tuna Man · Aug 20, 2019

Sorry, F250 pros: very reliable, good on fuel, especially when trolling for tuna or marlin, easy to get parts, not too hard to work on, props readily available in many configurations.

Cons: expensive to purchase, expensive to have installed, wiring harness most likely will need to be upgraded, gauges may not be compatible, might need different props.

Fishtales · Aug 22, 2019

I have the 250 3.3l on my boat. I did the mid sections a few years ago. Been bullet proof for 13 seasons. Will likely repoowering with the 4.2s when I must.

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Yamaha F-250s...... Repower?

Gary M

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seasick

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Ky Grady

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Legend

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Papa J

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SmokyMtnGrady

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Gary M

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brdawg2001

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Tuna Man

GreatGrady Captain

Tuna Man

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Fishtales

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