engine trouble

this is my engine today out on Derg - the manufacturer (Bonwitco) says that I should be getting 20-25knots from this package.

I was only getting 6.5 as per the GPS

is it that the engine needs just a slight adjustment with the throttle cable?

Is all that smoke ok from an engine that has been idle for a long time?

thanks...


http://youtube.com/watch?v=_vfswzDEZ3Y

how 2 stroke are mixing with petrol it might be a bit rich what hp is the engine

Make sure the engine tilt control is putting it right down as far as possible in the water - if its too high, you'll get cavitation causing propellor slip and low speed. Happened to me years ago.

What size is the boat? Friend of mine had a Bonwitco 17ft with a 60HP motor and got 28 knots out of it full belt, so I guess anything under 40HP would be underpowering it and wouldnt lift it into the proper planing position to allow it to work up speed.

That said, 6.5 knots is nearly rowing speed, at worst I'd expect it to be doing something in the teens....

Make sure the engine tilt control is putting it right down as far as possible in the water - if its too high, you'll get cavitation causing propellor slip and low speed. Happened to me years ago.

What size is the boat? Friend of mine had a Bonwitco 17ft with a 60HP motor and got 28 knots out of it full belt, so I guess anything under 40HP would be underpowering it and wouldnt lift it into the proper planing position to allow it to work up speed.

That said, 6.5 knots is nearly rowing speed, at worst I'd expect it to be doing something in the teens....

the mix is 50:1 as per guide, the Bonwitco is a 400C, 15.5ft long ----- its rated to 40hp max so 35 should be just as good - Wills Marine, makers of Bonwitco reckons that it should be 20-25 knots.....


thanks lads

At that size, the 35 should be fine right enough....

If the mix is correct (you premix it yourself? Some engines do the mixing internally from an oil reservoir) and its still belching smoke, my next suspicion would be worn piston rings. If its that, you'll need to take it to a mechanic for a stripdown.

Can you take a plug out and put up a pic?

spark plug?

Yes, if you can. It'll give a clue.

I'm assuming that the carb is OK and correctly adjusted.

the mix is 50:1 as per guide, the Bonwitco is a 400C, 15.5ft long ----- its rated to 40hp max so 35 should be just as good - Wills Marine, makers of Bonwitco reckons that it should be 20-25 knots.....


thanks lads[/quote]

i had the same problem with mine . the power went drasticly down got aclean petrol can and put a bit shy of 50 . 1 mix and reved engine to half revs and left it going in a barrel of water for about 5 minutes till she came back to herself .

thank Taz, I will try that and put on flush muffs, run her adn see what happens - does anyone have any idea about adjusting the idle speed?

I'd wait till you've tried that new mix before going fiddling with carb adjustments, hopefully it might sort that too. Is the idle lumpy or what?

There's usually an idle adjustment screw near the throttle linkage but again I'd like to see a pic...

Sorry, this is like trying to diagnose a serious illness by postcards!

I'd wait till you've tried that new mix before going fiddling with carb adjustments, hopefully it might sort that too. Is the idle lumpy or what?

There's usually an idle adjustment screw near the throttle linkage but again I'd like to see a pic...

Sorry, this is like trying to diagnose a serious illness by postcards!

how are these???

You do not have the required permissions to view the files attached to this post.

OK, good pix, PM on the way.

thanks Hugo

just to update, from last week......


http://youtube.com/watch?v=MJ3lwknWbEs

thanks for all the help, answers and patience with the stupid questions

glad you got it sorted

Glad you got it sorted....

What was the fix?

Kev

Glad you got it sorted....

What was the fix?

Kev

Need a long shaft engine!! got the carbs done to be sure