merc runs at half power

[gmarshall43]

I have a 1971 merc, 9.8 hp. It is hard to start unless I squirt some starting fluid in, then it will start by the second pull. Once it starts it will idle fine and run on slow speed fine but when I throttle up to full speed I hear a electrical crackling sound that may go away or it may not. But either way the motor doesn't run at full power. What could be the problem???<br /><br />thanks

 

[BF]

Re: merc runs at half power

sounds like it's only running on 1 cylinder. Electrical crackling noise? Check that you have spark on both cylinders and work back from there. I'd also check compression to make sure that's OK. <br /><br />By the way... using starter fluid in a 2 stroke motor is a no-no. 2-strokes need oil in the gas for lubrication, starter fluid has none... even worse it "washes" the cylinders of any residual oil. You'd be better off using a squeeze bottle of oil/gas mix... But, you shouldn't need that if you have compression, fuel and spark!<br /><br />HTH.<br /><br />Brent

 

[gmarshall43]

Re: merc runs at half power

Thanks for the ideas to check out. Also thanks for the tip about starting fluid.

 

[AndyL]

Re: merc runs at half power

You could try running it up in the dark to see if you can see where the arcing crack is coming from.If it is HT it should not be hard to see. That may give you a lead if all else checks out OK. It could be as simple as a bad earth causing the problem or even tired plug leads leaking to earth.

 

[mellowyellow]

Re: merc runs at half power

arching (sparks) and gas is bad mojo ....<br />at night it's easy to see any archs and where<br />they r comin from. look for decayed wires.<br />manuals r 4 sale at bottom of this page or look<br />at local library, I'd get ahold of one and follow<br />testing proceedure.<br />safe boating,<br />M.Y.<br />earth = ground btw.

 

[Chinewalker]

Re: merc runs at half power

Generally, if you're hearing the arcing of a spark, it's either coming from a cracked plug wire or a cracked coil. Either is relatively easy to pinpoint, particularly if you do it in the dark... Those coils can and do crack over time..<br />- Scott

 

[gmarshall43]

Re: merc runs at half power

Thanks for all the tips on what to look for. I did an initial check for the obvious. I found one set of points not opening when I turn the shaft and a spark plug wire that turns in it's boot. I still get a spark on it. I'll try running it at night like you suggest but in the mean time could these two items cause me problems?