Suzuki DT50 runs on 1 only

[mcbrid]

Hi,<br />I'm pretty new to boats and have a Suzuki DT50 from around late 70's (I think).<br />It has always run a little lumpy at idle and never seemed to really get up to full power when running.<br />One day it then stopped running on the lower cylinder although top was fine. SO far I have changed plugs, checked connections, cleaned carbs and it seems as though I get a spark to the plug (looks nice and strong).<br />If the engine is run out of gear both cylinders seem to eventually pick up and run but if I am in forward gear I get nothing from the lower pot.<br />I don't know where to start looking next - any clues please (much appreciated)<br /><br />Thanks

 

[G DANE]

Re: Suzuki DT50 runs on 1 only

Hi<br /> I suggest you try to test the compression first, and let us know the results. It could sound as a leak in cylinderheadgasket. Have you observed waterdrops or miscolour of the spark plug on the cylinder that is missing.<br /><br />You can detect the bad cylinder by pulling the ignition wires one at a time, using a dry cloth to hold the wires, to prevent shock.

 

[DJ]

Re: Suzuki DT50 runs on 1 only

Ditto, G Dane. My vote is for a bad head gasket. Not uncommon on 2 and three cylinder Suzie's.<br /><br />If it is leaking water into the cylinder, the spark plug will look very clean as opposed to the one in the cylinder that is operating properly.

 

[Yepblaze]

Re: Suzuki DT50 runs on 1 only

Dual carb, single coil that fires both plugs at the same time. Check the compression first.<br /><br />Then if that's good, pull the carb(s) or at least the one in question and give it a good cleaning by dissasembling it entirely along with spray carb cleaner and compressed air. If it still has the foam liner inside the hood, remove it as it is probably decaying leaving debris all over the place in there and bits will end up getting into the carbs and plugging the jets.<br /><br />Pay attention to carb sync'ing so they both pull off idle at the exact same time.

 

[mcbrid]

Re: Suzuki DT50 runs on 1 only

OK - Happy New year folks.<br /><br />I checked the compression and both cylinders were showing at around 10 bar and well in te green section of the gauge.<br /><br />Bth plugs were looking pretty wet and were NGK BS8H's, so I've fitted BS6H's instead to hot things up and the motor seems to be happier with this. I ge a lot of blue/white smoke when I power on so am thinking to drop the oil ratio from 50/1 to 75/1.<br />I don't do much power work with the engine (mostly 5 -7 mph stuff) so I hope it should be OK.<br />I noticed that the lower pot idle screw was set much further in so have reset it the same as the top (good) pot. Again this helped.<br />So now the engine runs on 2 but doesn't start as well as it used and is still a bit lumpy at times.<br />Next step check timing I think, unless you guys have any other ideas.<br />Thanks<br /><br />Mike<br />

 

[wippb]

Re: Suzuki DT50 runs on 1 only

mcbrid<br />I'm not much of a wrench but I think the others will agree that you should not change the 50:1 mix. This is the oil that lubricates your motor. Unless the manufacturer specifies a leaner mix when you change it you are not getting the lube that your engine needs. This could be a costly mistake. Two strokes burn oil and thus the blue smoke. Also changing your plugs to a hotter choice could also lead to a meltdown of your pistons. <br /><br />But what do I know. Just my $0.02 worth