Looking at a used boat with a V8 Johnson, ?

[103Control]

I just reserching pros and cons on what experts think of the old V8 outboards, 250 & 300 HP Johnsons.
Since they do not make them any more I thought I would ask here if I should be concerned about it or not.
6 out of the 8 Cyl. are around 130 - 135 PSI compression and two are 100 - 110 PSI. so that something to think about how long that would last be for needing a rebuild.
The seller told me it runs to 5300 RPMs nice and strong but one link I found on a forum claimed that if it only runs 5300 to 5500 RPMs " You'll hate it "? and it went on to say the parts are at a premium.
So yah or Nay on the V8 Johnson ?
Unless I get it a good enough price to figure in a new big V6 next year, A 250 or 275 HP V6 ? That's my next thread.
Thanks again, AL

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

Hey Al,

I had a Johnson 300 on my hydro stream and WOW what a ride! I had to get rid of it because of course i couldnt afford $250 every weekend to drive it. The V8's deffently GO really good if you have the right prop on it. I have a 27' prop and it went Up wards to the high 80's low 90's and it would keep going. Anything past 85 your taking your life into your hands because it got really unstable. The V8 is really a cool looking motor and has alot of bottom end power and is not a slow machine. Mine was a 1985 Johnson 3.6 GT V8. The V8's also had fairly good reving capabiltys like it would deffiently go to 5300 easly. As for the parts. I have never had problems getting parts. The only thing i would worry about is your Gas fill up. It costs alot for the speeds youd be hitting. Overall there a really nice motor with alot of power and they go really good. If gas prices drop i would defiently buy another one. Also if your getting a boat with this Motor check the transom. I cant stress how imporant it is to check the transom over for stress cracks and big cracks since its such a HUGE motor and it pulls so hard on the transom. I know after i sold my 300 I put my 150 Gt back on and 3 weeks later with some bouncing of the boat and driving it hard i was able to break the transom right off and lose my motor. (complete skill if you ask me) Anyways back to the 300 YES ITS A GREAT MOTOR just terriable on feul

 

[justinhip]

Re: Looking at a used boat with a V8 Johnson, ?

I just got mine running on a 23' CC. It flies. Mine is a 1992 250 V-8. It rockets out of the hole and planes the boat beautifully. I have not yet been able to experience the poor fuel economy as last night was my first ride.

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

Yeh there deffiently a rocket Ship. What size pitch prop do you have

 

[justinhip]

Re: Looking at a used boat with a V8 Johnson, ?

Yeh there deffiently a rocket Ship. What size pitch prop do you have

I believe 14.25X21 as per my brother or at least what he thought he read from the hub. What about u?

 

[MarkV_Deep6]

Re: Looking at a used boat with a V8 Johnson, ?

What size boat is the engine on? From reading previous posts, the compression up at 135 PSI would tend to point to some modification on the engine. The lower numbers seem to be where the stock engine would be.
The RPM is a bit on the low side and you will probably be doing a bit of adjustments to get it to perform closer to 6200 - 6700 RPM.
As far as parts go, I have not had trouble finding parts for mine and it is no harder to work on V6 a V6 of a similar vintage. My engine was not well cared for yet it is still a very strong reliable engine. Over all they are very good engines
If the size of the boat justifies the power, the fuel economy is not all that terrible.

I would recheck the compression of the engine. Those numbers seem a little suspect.

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

So justin you have a 21 inch prop on it you prob get High 70's with it But if you went with a 27 like what i had on mine you would notice alot more on the top end and you wouldnt lose that much on the bottom end. Yeh just to say i would check those compression numbers again like Mark said they sound a little suspious

 

[103Control]

Re: Looking at a used boat with a V8 Johnson, ?

Thanks for all the imput folks, much appreiciated.
I would guess that the prop might to big on this thing if it is only going up to 5300 RPMs and the fun factor is up over 6000, its a 3500 pound ocean boat though.

I would say that this outboard has been modded, The first thing you'll notice is the exhaust cut out and the jack plate.

http://cgi.ebay.com/ebaymotors/ws/e...m=150013198552&ih=005&sspagename=STRK:MEWA:IT

The ad says 1998 V8 but I'm thinking 1988 by the looks of it.

Road trip then, I'll check it out see if it's worth fixing up !

Cheers, AL

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

Wow thats a fairly big boat. When I had miine on my Hydrostream it was barely floating with that motor when it wasnt going any where. mind you the boat was rated for a 150 max. The motor seems alot bigger in person and alot bigger on my little 17ft boat. Its a nice looking boat but i dont think I would see you doing 70mph In that boat.

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

O btw thats a 1988 It cant be a 1998 Because they didnt make v8's in 1998

 

[103Control]

Re: Looking at a used boat with a V8 Johnson, ?

Right, No white knuckles and hairy twisty's like you doing 85... yikes! maybe 45 + which is more than enough in 3-4 foot chop.

You must have &^%$ when that O/B took out the transom?:^

 

[AlanR]

Re: Looking at a used boat with a V8 Johnson, ?

I was with a buncha friends and we all just looked at each other and was like WTH! We got the motor out 3 days later with my my scuba gear and a trusty winch. The hydrostream got the dash taken out and was used in my bar and the rest of the boat was burned in a big old bon fire. For the Gt 150 we pulled the plugs out, drained the water out of the carbs and cyclinders and it fired right back up. Its now on my Sidewinder.