• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.


Announcement

Announcement Module
Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

Page Title Module
Move Remove Collapse
X
Conversation Detail Module
Collapse
  • Filter
  • Time
  • Show
Clear All
new posts


  • 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

    My goal is to figure out which pitch on a prop is the best for my boat between 15, 17 an 19.

    I am a complete novice to boats having bought a 1987 17 ft Bayliner Capri with a Force 85 HP (model 356X7A) motor last Fall because I wanted a boat, the price was right and the owner babied the boat. Anyhow, I want to get a new prop and everyone I talk to has a differenet opinion. The boat has no tach so I have no idea what the RPM or speed is with a WOT. The tag on the motor say it ranges from 4500 - 5500 RPM. The engine has been rebuilt and the old owner says it should have 90 HP now, if that matters at all. I had the boat on the water in September and it seemed to run fine, but keep in mind with my experience I don't really know what fine is and how a boat should respond.

    Two props came with the boat and they are roughly 13" in diameter. The prop that was on the boat only has these numbers on it A623265 and PS623. The spare prop has these two numbers on it A825285 and PS625. In searching the best that I could come up with is that they are Propco props with the PS623 being 13.25 x 17 and the PS625 being 13 x 19, if I am right on these assumptions. My dilemna is that most places I spoke to about props are recommending a 15 pitch prop. Which is the safest route to take. I am fairly certain that 19 is not the answer.


    On a side note, if anyone can help me find a Teleflex 53743P Tach so I can add that to my boat, that would be great as well. Being 20 pole makes it tough to get a tach on it.

    Thanks


  • #2
    Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

    Yes, i have a very nice new Teleflex Tachometer 53743p in my hands here right this moment. I am returning it to a dealer ... where it will sit forever. I will be glad to give you their name and phone.

    30 to 35 bucks is the price I believe.

    This tach is for a "Force 20 pole" .

    Steve
    EDIT
    Last edited by JB; November 27th, 2010, 09:35 AM. Reason: Email violation

    Comment



    • #3
      Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

      17 pitch is probably the best estimate without a tach. I am almost certain that 15 pitch will be too little and will cost you speed. It would be good for water skiing, but for tubing, the 17 will be correct. For the 85 on a 17 foot boat, 19 pitch will be too high.

      Comment



      • #4
        Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

        i have an 1988 16 foot bayliner/trophy Center console.. with an 85 hp force and i run the 13x17 and my engine rpm wot is 5000 5100 and a top speed of 35 mph... My boat planes out well and cruises nice at top speed... the only thing i wanna change is go from aluminum to stainless with the same pitch im not sure it will help or hurt me...

        Comment



        • #5
          Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

          The 17P is what you need till you can put a tach on it.
          The 15 won't work!!!
          If your boat is set up for a 17 a 19 will cost more to run.About 10-20% more fuel usage.You might go faster but at a cost.
          If you want to use stainless and a 17Aluminum is what's needed now. You need a 15p Stainless.
          5500rpm is OPTIMUM!! With the correct load:1/2 tank fuel/1-2 people and equipment.
          You need a tach.Anything else is using the WAG system(wild *** guess).J
          IF YOUR OUTBOARD DOESN"T START WITHING A FEW SECONDS THEN SOMETHING"S WRONG!!!!

          Other websites are NOT the place to buy parts.They managed to screw up my last 4 orders.
          NO communication,NO follow through. Incompetent staff.Nuff said!

          Buy American made Cars and Trucks!!!Towing insurance for a boat,a GREAT thing.

          If you fix your problem,do the rest of the posters a favor and send in one more post telling who,what, how it was fixed.J

          88 Bayliner 21CC Twin 85hp Forces.

          Comment



          • #6
            Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

            I used to think mine had a 13x19 but I was mistaken. Tinkering around in the shed I see the lonely prop just sitting there on the ground and I just had to check and make sure. Turned out it was a 13 1/8thx15 aluminum. Michigan 072055 is what the number was. 1986 85hp force on a 15' capri bowrider.

            Comment



            • #7
              Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

              I have a Bayliner Capri 1600 project boat with a Force 85. The 17 pitch is common on this boat and will perform well for the type of boating it's aimed at. That is, cruising around and maybe pulling a skier now and then. A 19 pitch will likely be a little too much. I have my 1983 Force 85 on a 1972 Glastron GT-150 right now and changed to the 19 pitch prop since it is smaller, lighter and designed to go fast. It'll do about 41 on it. Expect about 35mph on the Capri with the 17 pitch.

              Marty
              http://www.martyhammersmith.com
              Marty
              http://www.martyhammersmith.com

              Comment



              • #8
                Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                My '88 version of your boat came with a 17.
                Bob, Orange County NY
                '88 Bayliner 1700 Capri Bowrider, 85 HP Force O/B, "Sea Weasel"
                Want a vessel safety check? Click here. Want to join the Coast Guard Auxiliary? Click here.
                Disclaimer: Although I am a member of the USCG Auxiliary, the opinions and advice in my replies are my own and do not necessarily reflect CG or CG Auxiliary policy or regulations unless so specified.

                Comment



                • #9
                  Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                  Philly try a piranha prop. They have a hubb kit for around $80 and each blade is only $20. A prop kit is $139 I think but the good thing is you can get 3 blades of 15 pitch for skiing and you can buy another set of blades for $60 in a different pitch. 15 would be for skiing and towing...17 for a little less acceleration and a bit more speed or 19-21 for higher speeds and less acceleration(good for fishing to get to where you need to go faster). They also have a wizard to calculate what size of prop you should use according to the weight of your boat and equipment and how fast you want it to go eg. skiing,general use and fishing. It told me that if I switched from my 13 1/8x15 to 12 5/8x21 that I could hit 51mph with my 85hp Force. Check it out http://piranha.com/enginelist.php?ma...23&submit.y=12

                  Comment



                  • #10
                    Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                    I forgot to add this...15 would not be the best route to take right now since you have no tachometer and you can't tell what rpm you're maxing out at. A 15 pitch might put you higher than your reccomended rpm range with that size of boat. Id go with the 17 until you get some type of tiny tach or a in dash tach installed.

                    Comment



                    • #11
                      Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                      A tachometer is like having a motor doctor on board.
                      a bad day fishing is better than a good day at work ..

                      Comment



                      • #12
                        Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                        I have a 1989 force 85HP and still have the owners manual. It says that you will get best performance with a 13.5 x 15. I just bought new one and it has worked out well for me. I am able to get to 39mph but probably higher now since i got all of the problems on my boat fixed. I am sure i am over 40mph now.

                        Comment



                        • #13
                          Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                          Give this a look: http://greatlakesskipper.com/product...ter-gauge.html This is right setup for our force's.
                          sigpic"That's what a ship is, you know. It's not just a keel, a hull and sails, that's what a ship needs. That's not what a ship is. What a ship really is.... is freedom."

                          Comment



                          • #14
                            Originally posted by Karla45 View Post
                            Re: 1987 Force 85 HP - Which Prop to use 15, 17 or 19 pitch?

                            I have a 1989 force 85HP and still have the owners manual. It says that you will get best performance with a 13.5 x 15. I just bought new one and it has worked out well for me. I am able to get to 39mph but probably higher now since i got all of the problems on my boat fixed. I am sure i am over 40mph now.
                            Howdy,

                            We have a Bayliner Capri 17 or 18' (it's 17.5" to be exact, so not sure if you round up or down) with a 90 HP Force.

                            Currently, it has a 13x19 prop...and it's absolutely horrible.

                            Boat runs good, idles good, etc...just doesn't like to go at all.

                            With just me in it(5'8" and 160 lbs), IF the speedo is correct, I could only get 15-17 mph.(We have no tach).

                            We were told we needed a different prop, so my question is this. Would going down just 1 size to the 13x17 make a HUGE difference, or a little...or should I trust what this guy said the owner's manual said and go down 2 sizes to the 15?

                            Just asking how much of a diff. each size makes, in people's opinions. Summer's almost over and the kids wanna do some tubing

                            Thanks in advance for any reply

                            Comment



                            • #15
                              You revived an old thread. You will be better off starting a new to get more responses.

                              But to give you a quick answer to your question, your problem is more on the engine rather than the prop. First, you need to do a compression test on all cylinders. Second, inspect all plugs are firing and there is no misfiring (especially at high speed). Invest in a tach, even a tiny tach will do so you have a reference for RPM. As for measuring speed you can always verify your speedo with a GPS.

                              If you absolutely can prove there is nothing wrong with the motor, a waterlogged boat can also prevent you from getting on a plane or reaching higher speeds. Or if the motor is not properly trimmed and heavily "plowing". However, if everything is working perfectly, even with an oversized or overpitched prop for this motor can at least reach 20~25 mph at WOT. It might have slow hole shot or getting on a plane (with overpitched prop) but will eventually catch on and reach higher speeds.
                              Last edited by Jiggz; August 1st, 2014, 01:40 AM.

                              Comment

                              Working...
                              X