viberation problem 25 hp sea king

[patrickwebb]

i have a 1960 25 hp gale (johnson) sea king, im having a problem at low speeds, im getting a viberation and it sounds as if the prop is bent but its not, its a brand new prop, it goes away when i get on the throttle a little bit more, but it sounds terrible when im at low speeds. This is not a cause of sea weed because there is not any on the prop when i am doing this, i have that motor on a 14 ft aluminum boat, but i dont think it should be viberating like it is, do you guys have any ideas of what it could be, i just replaced all the seals in the lower end, (not because of viberation, becase it was leaking) i really want this to stop, thats if it is a problem or not, i was told that it is perfectly normal, but find that hard to bealive.

Thanks for any input you may have on this problem i have!

Patrick Webb

 

[tashasdaddy]

Re: viberation problem 25 hp sea king

check spark, make sure it is running on both cylinders, as carb adjustment my smooth it out. http://forums.iboats.com/showthread.php?t=167352 if not look at a carb rebuild.

 

[patrickwebb]

Re: viberation problem 25 hp sea king

i forgot to mention, i just rebuilt the card, do you think my low speed is not set right on my carb?

 

[tashasdaddy]

Re: viberation problem 25 hp sea king

those are the best directions in have ever used. i have done it to many motors, and never had to touch them again.

 

[patrickwebb]

Re: viberation problem 25 hp sea king

my dad is a master mechanic, he went to school for outboards and have been doing them for about thirty years, he was the one who adjusted my my carb, well in fact he was the one who did everthing to my motor, i just dont think that it should be shaking like it does at low speeds, do you think i should have him re adjust it? He swears that it is perfectly normal. and thats what it should feel like, but i dont remember any other motors of that size viberating like mine does.

 

[F_R]

Re: viberation problem 25 hp sea king

Are you speaking of the motor shaking back and forth at slow idle? You gotta believe us, that is normal movement on the rubber mounts. If it were not for the rubber mounts, the vibration would be transferred to the boat, causing your tackle box and everything else to go dancing across the floor. Just ask anybody with a pre-'55 without rubber mounts.

Now, having said all that, I have to ask do you have any broken rubber mounts? That will make it shake more than normal. There are three upper and three lower ones. In addition to those six, there are four small ones mounting the lower motor cover pan. If those are broken (common) the motor cover will shake all over the place.

 

[patrickwebb]

Re: viberation problem 25 hp sea king

its not the motor cover that im worried about its the whole boat that viberates at a low seed once the rpm are pushed up a little higher than they were at viberation mode the shaking goes away and everthing is normal.

 

[tashasdaddy]

Re: viberation problem 25 hp sea king

your rubber mounts may be bad. you are going to get some vibration.

 

[patrickwebb]

Re: viberation problem 25 hp sea king

i took it out last night and the viberation is so minor im thinking that its normall, would bad coils make it viberate, and how can i get some more power out of this old 25, i raced a yamaha 25 hp and he beat me, not by much but he did beat me, i would think my motor would have smoked him, it was the same boat with the same amount of people on it (2) do you think i could get a little more out of my motor by adjusting the high speed, i smoked him off the line but as soon as he plained out he crept pass me, mayne i hate losing!


thanks all you guys for your help, this is a sweet site that i have told probaly about 50 people about, and there all going to register on this site as well , if they allready havent!


you guys are the greatest!

Patrick Webb---Gibraltar Michigan, our season is almost over!

 

[tashasdaddy]

Re: viberation problem 25 hp sea king

getting more power, make sure it is properly tuned, but i'm sure you dad has it right. don't feel bad, as the 25 yamaha, does have more horsepower than your motor, you motor HP rating is at the power head, the yammy is at the prop. so you do loose some HP in the transition from the power head to the prop. so tell you friend you lost, with less HP. compared to new engines, your would probably rate between 19-22 hp.

 

[F_R]

Re: viberation problem 25 hp sea king

The correct adjustment on the high speed knob is turn it to the right till it starts to falter, then turn it back to the left till it regains power. Then leave it alone.

That will increase horsepower only if it is adjusted wrong and you correct it.

Racing Yamahas is an unfair contest. Avoid embarrasment and don't do it. He has over 40 years of engineering improvements on his side.

 

[jbjennings]

Re: viberation problem 25 hp sea king

Just the fact that a 48yr. old motor was out there "racing" should be proof positive that 1960 engineering was pretty darned good.
How about posting a pic of your sea king? I'd like to sea it....
JBJ

 

[samo_ott]

Re: viberation problem 25 hp sea king

I have a few questions. Was the vibration there before you resealed the LU? Also, are you sure it's a Sea King and not a Buccanear (sp?)? As I have a Gale 25 Buccanear from the early 60's.

Also besides racing a new Yammy is not a good idea as mentioned as the HP rating of the older engines is lower, what is your compression? Highly unlikely that it is as it was when built and thus you're losing hp's there also.

Race 20's and you'll have more luck

 

[F_R]

Re: viberation problem 25 hp sea king

Even if everything else were exactly the same, the Yamaha would outrun the Gale because of the design of the gearcase and propeller. That's what I was thinking when I mentioned engineering.