1962 28hp sea horse fine tuning help needed

[kevinwd1]

I finally got the motor up and running on my boat and am very happy with the result. The only issues are that the motor tends to miss at one particular throttle position. It?s at the lower rev range at about a trolling speed. It also misses a bit when decelerating when hitting the same throttle position. The motor ides great when warm but tends to have the same type of miss at idle when cold. I'm not sure how you would to fix the problem or if it?s just one of those things that motors of that era did.
Also the last 1/4 of the throttle doesn?t make much difference. The revs pick up a bit but not much and the motor doesn?t sound quite right ,or it could be just the fact that I'm in an aluminum boat and the extra revs make thing rattle more:joyous:. Could improper carby float position cause a motor not to rev out with no other symptoms?The motor gets the boat up and on to the plane quickly and dosen't seem to lack any power
Any tips would be greatly appreciated

Regards Kevin

 

[F_R]

Re: 1962 28hp sea horse fine tuning help needed

You seem to be describing a "lean sneeze" at idle. That is caused by the fuel / air ratio being too lean. First thing to try is simply richen it up a tad by giving the slow speed needle a tweak to the left. That may be all it needs.

The last 1/4 throttle thing is built-in. At full throttle, everything is wide open Go. Back it off a notch and that is the "Cruise Throttle" position. Runs darn near as fast, but saves a bunch of gas (on a light, fast boat).

 

[kevinwd1]

Re: 1962 28hp sea horse fine tuning help needed

Thanks F-R. The miss does sound like a lean sneeze it's just that it occurs a little above idle revs only. The motor will idle great once warm, anyway will adjust the low speed needle and see how it goes .Does the low speed setting affect fuel consumption at all?
The motor does cruise extremely well at 3/4 throttles and sounds sweet.

 

[kevinwd1]

Re: 1962 28hp sea horse fine tuning help needed

Have done about 10 hours on the motor since getting it going. The lean sneeze at idle is almost gone .I'm still having a bit of trouble with it not quite revving out. The motor bogs down slightly when going from 3/4 throttle to full throttle and then settles down. I did a speed test and the boat with do 23mph at 3/4 throttle with no change in speed at full throttle. This speed seems slightly slow .I'm thinking that maybe the motor is running slightly rich? I haven't played with the high speed setting since getting it going as the only people who have been in the boat are my young kids who aren't quite up to driving the boat while I play with the motor. I might be able to get my brother to give me a hand tomorrow so I'm thinking of playing with the high speed needle to see if I can get it to run a bit better. If it doesn’t what other things should I look at. Would the link and sync affect top speed .I'm assuming the link and sync setting gives you the up and go but doesn’t affect the higher rev range. Maybe the motor is a bit tired and 23mph is as good as it gets. Any advice appreciated.

Regard
Kevin

 

[boobie]

Re: 1962 28hp sea horse fine tuning help needed

Maybe I missed it, but have you done a good link and sync on it ??

 

[F_R]

Re: 1962 28hp sea horse fine tuning help needed

The sync is very important as boobie suggests. That must be correct before anything else can effectively be dealt with. But then the high speed needle must be dialed in, at full throttle. Maybe you have to invite somebody to go for a ride with you. He will enjoy it and might even kick in for the gas (??) Even so, you won't see a huge difference in speed between full throttle and cruise setting. Maybe one or two MPH. Everybody wants to go faster, but 23 MPH isn't too shabby. Did I miss it, or what kind of boat is it anyway?

 

[kevinwd1]

Re: 1962 28hp sea horse fine tuning help needed

Boat is a 13ft tinny with a reasonably flat bottom.I did the link and sync as per the manual but when first testing the motor it would bog down when throttling up.We could get the boat up and going by adjusting the high speed needle but as soon as we throttled back we could not get going again.So we adjusted the lync and sync cam on the water and that made all the difference .The boat would get up on the plane quickly and didn't bog down at all.It only required a small amount of adjustment and probably isn't quite the ideal way to do it but the final setting we arrived at seemed to give the best results.I'm still not sure if the link and sync setting affects top speed or if it just gives the motor power to get up and going then the high speed needle becomes the critical factor when at high revs?
Anyway my brother decided to go kiteboarding so I took the kids for a 2 hour boat trip up the Brisbane River.Will try and play around with the high speed needle at another time

Kevin