merc 200 20hp want start

[furrjt]

i bought a boat that has a 20hp merc 200<br />ser.#1294739. it has good compression,is getting fuel,but seems not to have any spark to the plugs.<br />i have good mechanic skills but know little about<br />this motor.<br />can someone please give me some advice on what to check or do?

 

[WillyBWright]

Re: merc 200 20hp want start

That's a basic magneto. Have a look at the points. You'll have to remove the flywheel.<br /><br />Also take a close look at the insulators where the points connectors pass thru the aluminum base. Those like to crack and the voltage can leak along those cracks rather than fire from the coils.

 

[tmcalavy]

Re: merc 200 20hp want start

Willy's right. You need to pull the flywheel and check the coils, clean and regap the points. A harmonic balancer puller from an auto parts store works well as a flywheel puller. If the coil coverings are cracked, time for a new coil...but I'm betting you just need to clean/regap the points, most of the time that's all they need to get the fire back.

 

[furrjt]

Re: merc 200 20hp want start

thanks guys! <br />i tried what you said but still no luck.<br />i pulled the points cleaned and regaped them.<br />what else can i look for or do?

 

[furrjt]

Re: merc 200 20hp want start

hey guys, i looked at the wiring it seems to be o.k. how can i be sure that the coils are good?<br />or do i just need to replace the coils and points.

 

[Chinewalker]

Re: merc 200 20hp want start

The condensers are the weak spot on those 1960s magnetos. A new set should leave you change from a 10-spot and will likely give you fire if all else checks out. Available from dealers, NAPA, and maybe here on iBoats. The NAPA/Sierra part number for a tune-up kit is 18-5008, includes two sets of points and two condensers. If the coils don't "look" bad, they're probably alright. Make sure the points are spotless and gapped at .018". <br />- Scott