Stumper Question of the Week 1969 Johnson 55HP 3 CYL

[ross_trucking2002]

My motor met the water today.. motor idles fine.. under load it came up on plane reasonably well, for an old low-bottom-end-torgue type of motor....ran well for an hour at 15 to 34 mph.. on my 16ft boat.. shut it off for 10 minutes, restarted it, and it was acting kinda bogging, and jerking under load....then within another 20 minutes, it was sounding good, and semi perky like it was when I first started it....Please make reference to my earlier topic today..."Carb setting for 1969 Johnson 55hp 3 cyl", which I have had No replies.... I have replaced almost everything on this motor... all electrical components..including the amplifier..all rewired, stater, coils, etc.. I think its just a little carb fine tuning..but any help or suggestions are appreciated.. Thanks Ross Bancroft Ontario

 

[REELSPORT]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

did not read your post from earlier today but the manual on the 1969 55hp says to turn low speed screw to seat (lightly) and then turn outward 5/8 of a turn and then adjust carbs while in water (not on muffs) until you get the highest rpms and the smoothest idle. Hope this helped to answer your question. Sounds like the bogging down my be a carb problem if not do a spark test and make sure you are getting a blue spark of 7/16 inch. good luck

 

[ross_trucking2002]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

REELSPORT, thanks for the reply... my other listing was under "johnson outboard troubles/repairs"..."Carb setting 1969 Johnson 55hp 3 cyl"...in that listing I stated that from lightly seated, they are out 1 turn or 360 degrees, so I am close to where they should be.. WOT seems very good, but has a very little miss from time to time.. Thanks Again, Ross

 

[REELSPORT]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

Ross My 69 55hp on an 16 ft runabout will only run about 30mph what pitch are you running on your prop? thanks

 

[ross_trucking2002]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

ReelSport, I honestly dont know what pitch it is..as far as I know, it is the original replacement prop.. which is in just okay shape, I will ask my freind at my local dealer to tell me exactly.....(he knows how to measure the thing) 34 to 36 mph with a headwind seemed about average today..temp was 87F.. the best I have seen with no wind at all is around 37.5 to 37.9 mph..and that is not reving up very high at all. I will try to find this out for you tomorrow, when I cruise the lake again, and stop by the marina.... Ross

 

[REELSPORT]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

thanks

 

[Big-E]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

Ross_trucking: I used to have an old 69 55 hp Evinrude (same motor) on my 16 foot flats boat. Bought the motor for 50 bucks not running in a backyard with controls. I was amazed that after new plugs, wires, and a starter it ran. But had the same problem your talking about. I simply rebuilt all 3 carbs the way the manuel states and adjusted all the linkage and she ran for 3 years like a top with no maint. Motor fired on the 1st shot all the time and never left me calling sea tow. <br /><br />As for your top speed i gota say WOW!!! My boat would do 32 on gps when it was glass flat in the gulf so near 40 mph is very fast for that motor. Are you using GPS or the speedo on the boat? <br /><br />later, <br /><br />Big-E

 

[ross_trucking2002]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

ReelSport, I was out on the lake again today, and all I can tell you that the prop is 12 1/4" in size, and the pitch (they guessed I think) to be 15... Not sure if this info helps you much... And Big-E...My old Starcraft boat, 16 ft, has the original speedo, with a new line and pitot...And again today it registered 38 MPH ...I have also installed a digital speedo (for test purposes) and it registered 37.6 to 38.3 MPH...todays temp was 88 F in calm water with very little breeze... The motor seems fairly strong for what it is...mind you it is not much of low end motor.. It does best from 10mph and up...but its not much of a powerhouse from 0 to 10mph... Ross

 

[Big-E]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

Ross_trucking: thats great but i disagre about the lack of low end grunt. I had a 4 blade SS wheel on her and she would fly outa the hole. We could wakeboard behind her in the gulf with no problems. Maybe that 4 blade prop was slowing me down but she did run in her intended rpm range (i forgot what that was). Good luck with her and if those carbs havn't been rebuilt in several years id order the kits and take a rainy day and do them. Thats what made a world of diff on my motor. <br /><br />later, <br /><br />Big-E

 

[ross_trucking2002]

Re: Stumper Question of the Week 1969 Johnson 55HP 3 CYL

Big E, It may seem somewhat funny, since I have replaced pistion, rings, and everything that is electrical on this motor, including completly rebuilding a new wiring harness from scratch, and I even replace the amplifier... but the 3 carbs I have never touched, except for adjusting them.... Maybe I should, and it would perform better out of the hole..It can pull up a single water skiier, but not as fast as I would like.. mind you I am only running a stock 3 blade prop. and the carbs have not been rebuilt in over 12 years... Ross