time for new plugs?

Dave K.

Chief Petty Officer
Joined
Sep 21, 2007
Messages
437
Afternoon gents, 85hp, this set has at least 50hrs on it. she didn't fire up right away like she usually does & that got my attention. i don't like staying on the starter anymore than a couple of seconds.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,082
Re: time for new plugs?

FIRST thing to do is a compression test.It will tell if there is a start of a problem.
Most forces that are set up right will/should start right away.Plugs shouldn't make that much difference unless they are really carboned .
Pull them and post the results.Jerry
 

Frank Acampora

Supreme Mariner
Joined
Jan 19, 2007
Messages
12,004
Re: time for new plugs?

Ahhhh, Dave. Albany--brings back lots of good memories. had a summer place on Taconic Shores on Lake Robinson near Copake. We Water-skied on Copake Lake. We would also trailer to Hudson and ski the Hudson river around Coxsackie Island and camp on the island. Occasionally we would cruise to Albany.

Now--to get down to business. Force engines have an ignition system that acts very much like a magneto. One of the characteristics of magnetos is that at low speeds they put out lower voltage. SO: Just when you need it the most (like for starting or firing fouled plugs at start) you have the weakest spark. It is also a characteristic with the surface gap plugs that they are dead cold and foul easily. But because of the high power of the ignition at speed (at least 60,000 volts), if you can get the engine started and running above idle, it will fire the surface gap plugs if they are not completely carboned up and will run perfectly. Typically, you crank and the engine fires and stalls, so you do it a couple of times more, then you go to fast idle and when it starts, you very quickly slam it into forward and the engine will pick-up and run.--It's telling you it needs plugs.

With ANY Force (before Merc got to them and changed the ignition) If you have trouble starting or idling, the FIRST thing to do is to either clean the plugs or change them.

BTW: water skiing is very hard on plugs because of the extended idling times while preparing inexperienced skiers. If you do a lot of skiing I would not be surprised if you need to clean plugs after every day.
 
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