1983 21B with a 250 EFI Yamaha. dos and donts?

[rawsurf Junior Member Find all posts View Profile Close rawsurf]

I have had my 21B for a few months it came with a Evinrude 235 84. Man that wasn't any fun pass anyhting but a gas station.

So I just bought a Yamaha 98 250 Efi. Is this to big for my transom.

Overall the transom condition is a 10. I am worryed about ruff seas etc. Any input? encouragment or dude your crazy will be greatly appreciated.Plus Do you think the fuel managment system is worth the money$$

THX

Rawsurf1

[ob1jeeper Senior Member Find all posts View Profile Close ob1jeeper]

Raw,

I have no experience with the Yamy 250 EFI, but I can attest from identical experience's, that the 235 jonRude you are removing is indeed a thirsty puppy...

As for weight, the 250 Yamy will be fine, as it's within the rating of your hull, and within a few lb's of the JonRude 235... With ONE HUGE difference... a WHOLE lot more zip...

Perhaps someone else here has had experince with the Yamy to share?

Good Luck, OB1

[RingLeader Administrator Find all posts View Profile Close RingLeader]

I'm sure there is no difference in weight of the Tamaha 250 Vs. the Merc 225 EFI that I had on my Mako 21. I know a guy who bought the Mako that I originally was going to buy.. I put a Merc 250 on that Mako 211. He loves it. Runs 54+ mph, but very affinitive towards gas.

If the transom is compromised, it doesn't matter what you put on there... it'll be too much. But if the transom is in good condition, you'll be fine.

[Mississippi Mako Senior Member Find all posts View Profile Close Mississippi Mako]

Doesn't that exceed your max horsepower rating? could cause trouble with your insurance co. or worse, the coast gaurd. ore is the 83 rated for more than the 80 model?

[rawsurf Junior Member Find all posts View Profile Close rawsurf]

I have a large t top plus a lot of rigging as well as an extra 35gallon removable tank for the bow. I usually travel with 3-4 guys so i figured more HP the better, I will be able to cruise faster at a lower RPM. I found a killer deal and pulled the trigger. then I started reading the forums and researching and didn't find to many people doing the same thing. The boat is rated for a 235hp only so I figured the weight wasnt bad but the power?

As far as coast guard and insurance I think I will cross that bridge when I get there.

It has a 23" prop would any recommend a diffrent set up?

Appreciate the replys

[Mississippi Mako Senior Member Find all posts View Profile Close Mississippi Mako]

insurance may not be a problem at all, alot of them will allow 15% above the max rating.

[makemenuts Member Find all posts View Profile Close makemenuts]

pull the "250" stickers off the motor...did motor manufacturers make a 250 in the 80s?

[Alcedo Senior Member Find all posts View Profile Close Alcedo]

Where do ya stow that fuel tank up front.......? How is it rigged ?

[rawsurf Junior Member Find all posts View Profile Close rawsurf]

Alcedo

I have four chalks with fasteners in front of the console front seat before the hatch. The fuel cell is a portable hard plastic. I have a line run down to the filter with a check valve. I secure the tank down with tie downs that you can tension. I take it easy on the way out burning the bow fuel. I can send you pictures if you like. will take me a bit for it isnt out of the shop from the repower. Hopefully this weekend. I cant even sleep at night thinkin about it it has been glass here on the Galveston coast...

[Alcedo Senior Member Find all posts View Profile Close Alcedo]

quote:

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Originally posted by rawsurf


Alcedo

I have four chalks with fasteners in front of the console front seat before the hatch. The fuel cell is a portable hard plastic. I have a line run down to the filter with a check valve. I secure the tank down with tie downs that you can tension. I take it easy on the way out burning the bow fuel. I can send you pictures if you like. will take me a bit for it isnt out of the shop from the repower. Hopefully this weekend. I cant even sleep at night thinkin about it it has been glass here on the Galveston coast...

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Yes sir, pictures would be great....I could use an extra 25 or so gallons on my ledge trips..........I carry jerry jugs now.....kinda a PIA.

[neckbone Member Find all posts View Profile Close neckbone]

What fuel numbers do you expect to get with that 250? There seems to be alot of those 250's out there for pretty reasonable prices. I'm kicking around the idea of an OX66 250 as well.

[classic73mako Senior Member Find all posts View Profile Close classic73mako]

More Power that's the solution. I also think along the same lines of running a higher HP motor at a lower PRM. I have a 225 HP Yama on my '73 22 and have never needed any more power. I have also never had the insurance co question the motor size or HP but I think the boat orginaly was rated for 250 HP. I also have several deck tanks (plastic 36 gal and 2 of the older steel 18 gal) that I use for those longer trips where I need exter fuel capaciity. I have a 3 way valve under the CC which I have plumbed to either draw off the main (below deck tank) or off a regular gas hose that plugs into one of the deck tanks. It has worked very well for the last 25 years when I have needed the extra range while chasing the tunas far offshore. Remembering the weights for the 250 HP Yama, I think it's heaver that the 235 Rude by about 100 or so #'s as the later model 250's has a bigger block than the earlier 235's OMC's did. More Power -

Mike

[rawsurf Junior Member Find all posts View Profile Close rawsurf]

I havent done a big run yet it will happen this weekend. I am hopeing less than 20 gallons an hour. about 2 g per mile. I will let you know after the weekend???/