Recently we did a back outboard test to see what performance we can get from old and new outboards, I say old and new but the old engine was 51 years old and the newest about 6 years old, its relative? The larger Yamaha 5hp motor gave us 10.1 knots and the Mercury 2.5hp motor gave 5.6 knots, so the smaller engine was doing rather well.
The test was less successful than we expected, being let down by both Seagull motors, both had the same sort of misfire and would not reach anywhere near full revs, they needed a lot of choke and a wide throttle.
http://ckdboats.blogspot.com/2012/06/testing-times-for-marine-outboards.html
I contacted John at SOS (save our seagulls) in Essex, England, he suggested there was dirt in the carburetor jet? Cleaning one carb sorted that motor out and it was soon running cleanly and the choke could be opened on firing right away.
The other motor refused to run properly, even after stripping the carb down twice, the only indication I could get was when the fuel bowl was manually over filled, the problem went away untill the fuel level went down, now what? What was this problem all about, well I had already raised the level of the float in the petrol bowl, what else can I now do?
Checking the workshop manual I saw that on the Villiers carburetor page there was one difference between the two carbs on the Seagull motors, the one that ran well had an Air Compensator while the one that still would not run well did not, I wonder ? thought I.
Note that air correction hole, I think without the compensator being fitted, too much air is fed into the hole, the pressure then upsets the fuel level?
The new plastic air compensator had arrived the same day I discovered its need. Not cheap at about 8 Pounds Sterling, plus pack and post, a Pound to write the invoice into Pay-Pal and when it landed, the packeage was opened by the customs and a 20% duty plus 14% vat was added. I think this bit of plastic cost me R230 and more!
I removed the air compensator from the one motor and fitted it to the motor that would not run properly, it started right away and ran cleanly! So we can now complete the back to back test, this time a blog viewer has also offered me his electric outboard, we can try that off his battery and also a solar panel designed to suit the electric outboard.
How good is this.
Roy
The test was less successful than we expected, being let down by both Seagull motors, both had the same sort of misfire and would not reach anywhere near full revs, they needed a lot of choke and a wide throttle.
http://ckdboats.blogspot.com/2012/06/testing-times-for-marine-outboards.html
I contacted John at SOS (save our seagulls) in Essex, England, he suggested there was dirt in the carburetor jet? Cleaning one carb sorted that motor out and it was soon running cleanly and the choke could be opened on firing right away.
The other motor refused to run properly, even after stripping the carb down twice, the only indication I could get was when the fuel bowl was manually over filled, the problem went away untill the fuel level went down, now what? What was this problem all about, well I had already raised the level of the float in the petrol bowl, what else can I now do?
The air compensator is the round cover on the carburetor. The motor is a 4.5hp unit and is around 35 years old?
Checking the workshop manual I saw that on the Villiers carburetor page there was one difference between the two carbs on the Seagull motors, the one that ran well had an Air Compensator while the one that still would not run well did not, I wonder ? thought I.
Note that air correction hole, I think without the compensator being fitted, too much air is fed into the hole, the pressure then upsets the fuel level?I removed the air compensator from the one motor and fitted it to the motor that would not run properly, it started right away and ran cleanly! So we can now complete the back to back test, this time a blog viewer has also offered me his electric outboard, we can try that off his battery and also a solar panel designed to suit the electric outboard.
How good is this.
Roy
