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V8 Looper/275hp Johnson

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  • V8 Looper/275hp Johnson

    Man I sure would like to hear from DHADLEY and the rest of you knowledgable folks about what you think of this engine. 88 vintage, low hours. I've got V4 loopers now....I'm always impressed when I see one of these V8's .....beautiful. Anyway, I wanted to know are they like other loopers for torque and reliablity? Any particular problems with this model? Did this size go away so they could bring out the 250 looper? I'd love to know any first hand knowledge you guys might have on them. I know they'd be thristy but is regular gas OK or is high test in order.

    I look forward to whatever info I can get about these engines.


  • #2
    Re: V8 Looper/275hp Johnson

    They're like the rest of the loopers - torque monsters. But they are a world unto themselves. Set them up like a V6 and you'll be really disappointed. Set them up like they deserve to be and you'll be forever impressed.

    In stock form 87 octane is fine. Just make sure you realize how much they'll use.

    Does it have power steering?


    • #3
      Re: V8 Looper/275hp Johnson

      What kind of boat are you running the V8 on? Is this a 27 shaft? If you use the engine for cruise at around 4000-4500 RPM, you'll get your best fuel consumption numbers. When you start turning up around 6k and above it can burn fuel really, really fast.
      My 300 is on a 25 Hydra Sport WA. The entire rig is about 4500 pounds unloaded. This engine is the only single that can push this boat and not be wanting a little more omph.
      Listen to Dhadley on setup. Do a search on V8*, you'll learn a lot about the V8 in general. Be sure to use the asterisk in the search.

      By the way, these become available quite often on Ebay. I saw a counter rotating pair going for under 5K; buy it now. These were really good lookin engines. Singles in fair to poor shape go for 500 to 1800.
      25 Hydra Sport
      300 V8 Johnson.


      • #4
        Re: V8 Looper/275hp Johnson

        I don't believe it's power steering but I do have hydraulic steering on my boat. I have a 24 Grady Offshore with H/Top, so it's fairly heavy. I'm rated for 280/300HP on the boat, depending on the model. My thought is I could run them in the more "economical" range but still have the power I need if I need it. I'm very careful about prop pitch etc and making sure the engines don't get lugged. DHADLEY what do you mean setting them up like they deserve..I definately want to know more.

        MarkV-it has a 25" leg...I have a 27" transom so I'd have to put it on a jack plate. As far as gas goes...I'm running twin 140 loopers and I figure the consumption would be roughly the same....

        I love the feedback. Keep it coming...very interesting.



        • #5
          Re: V8 Looper/275hp Johnson

          not to be a wise a.. i just wonder why you want to get rid of a twin setup and go for a single motor?

          you go offshore?
          i would feel more comferteble having 2 engines on my transom.

          i would give it a second thought.

          im not saying you should not do it, if it was my rig i would preffer twins above a single bigger powerhouse.


          • #6
            Re: V8 Looper/275hp Johnson

            If it has power steering it'll have a cylinder on the front and a pump on the starboard side of the powerhead. Very nice set up.

            As for the set up, yes you'll probably need a jackplate. The 25" model is actually 27" as mentioned. For that set up I might be tempted to try it without if you can get the motor high enough, depending on what prop you have. You have some advantage that he transom is already 27". Now you know why the boat builder did it that way.

            The rev limiter on the 275 is probably at 6200, you might look at the pack and see. It may be at 6700. You'll want to prop it as close to 6200 (with a normal load) as possible regardless. That will max your cruise rpm. If you set it up at around 5600 you might as well save the weight and get a V6. You'll hate it.


            • #7
              Re: V8 Looper/275hp Johnson

              Use the electric primer pump that comes with it. No bulb, no 90* fuel line fittings, no bulkhead fittings, nothing under 3/8" up to the motor. If given a choice we run 1/2" line as close to the motor as possible (to the pump or filter) then go to 3/8".


              • #8
                Re: V8 Looper/275hp Johnson

                "MarkV-it has a 25" leg...I have a 27" transom so I'd have to put it on a jack plate. As far as gas goes...I'm running twin 140 loopers and I figure the consumption would be roughly the same...."

                Your boat is very similar to mine in style and weight. If your Transom is truly 27" then the engine is a perfect match. As Dhadley stated the "Leg" is 27" Unless your looking at the short shaft.

                Dhadley assisted me when I first bought the rig I have. I had to shift the hole positions a couple of times to get it dialed in. It would turn about 6000 RPMs but was a little to high for heavy seas. The prop orriginally was a 15 X 17 and had been reworked. I now run an OMC 15 X 16 to get the best from the rig.

                I had a chance to get a newer 15.75 X 15 newer BRP Prop designed to give better mid range "cruise" performance and fuel burn, but it was designed for the newer Etec's, so I passed. My top speed is about 50 mph on this heavy boat.

                Your top speed will more than likely increase VS the twins, however, you give up the safety factor of twins. Not sure about the fuel consumption. My experience with twins is limited.

                Ran 24 Whaler with twin v4 90's in the Bahamas. We repowered it with a V6 225. the fuel consumption and speed was much better with the single. The 90's may have been cross flow engines and not loopers.

                If you happen to go with your existing 140's you will probably be very happy with those. They seem like a good weight - power ratio. The V6 150's would be to much weight.
                25 Hydra Sport
                300 V8 Johnson.


                • #9
                  Re: V8 Looper/275hp Johnson

                  MarkV- It's always the same issue for me...get rid of the two 140's and go to a single...or not. I'm in the San Juan Islands and while it can get nasty...it's not really the open ocean... I've already got a new hi-thrust kicker for trolling and emergency usage. A big single with a kicker seems to me to be the best fit...I just think a 225 would work so hard to push that big heavy boat...I've always thought of the 275 and I just bumped into one (potentially) so we'll see. You run a single 300 right? What are your experiences?

                  I'm open to all the info I can get. I'm leaning away from double matinence etc and looking hard at this 275.

                  I'd like to hear your thoughts.



                  • #10
                    Re: V8 Looper/275hp Johnson

                    I run a 9.5, 64 Johnson kicker for trolling. It does what I need in the Chesapeake area. As far as power, the V8 has no problem with the weight of my boat and would probably be just fine on yours. The V8 has the torque to pull skiers even with the weight.

                    I have seen boats of this size with a large 6, 225 - 250 and they do ok I guess, I've never been aboard one. There not as quick out of the hole, and are about 10 mph slower @ WOT. Personally I prefer to be on the high side of the rated recommended power for the boat. I like knowing I have a reserve to hit when needed. In rough conditions you speak of, the difference will be considerable.

                    If you do go with the V8 be sure to set it up as Dhadley has recommended. The electric pump OMC supplied to prime this engine was discontinued last year. I think I got one of the last ones. A subtitute may be used, you just have to configure it. I posted something about the parts needed a long time ago.

                    Parts may be a concern for you where you are? I have not had any problems getting parts. The're not available at your local dealer, but via iboats and other good suppliers, you should be able to maintain it as long as the other large older johnsons and evinrudes are available.

                    Good luck no matter what you decide.
                    25 Hydra Sport
                    300 V8 Johnson.


                    • #11
                      Sign up today
                      Re: V8 Looper/275hp Johnson


                      Like I stated earlier I really do have a hesitation about a single motor smaller that 250 on the boat. Ever since seeing my first 275...I always thought it would be "just right" for the Grady. I figured it out, the boat, both tanks 3/4 full and the 275 w/o people weighs in around 4700 lbs. So if this 275 works out...based on what I'm hearing from you...it should power the Grady along right nice.

                      As far as parts, I've got a OMC dealer here...but I've found that the internet is such a powerful tool for locating whatever I've needed. I replaced a power pack on my v4 for $80.00 and my own time ( I really like working on these motors) and my dealer was looking to stick me for $300 for the pack plus an hour of shop time.

                      While I'm still a neophyte in regards to outboards...I've got some mechanical skills and I'm actually interested in learning more about them...that said, with this great site and my OMC repair manual I hope to be able to fix most anything that went wrong.

                      Again, if this 275 works out...I'll be asking for more assistance and I will certainly heed DHADLEY'S advise and set it up as a V8.

                      I'll let you know if I get it or not.

                      Thanks again for the assistance folks...I appreciate it.

                      PS- What do you think of Boyesen Reeds....