When a spark plug makes a difference.

[ClownPilot]

Want to share this experience with all of you. Whenever your enthusiasm for sailing overides your fear of reoccuring engine troubles, then your only fear is whether or not your engine will get you out of that crowded marina. And not whether or not you will be able to return.After all, you have a cell phone ... you can call in sick and munch on pop tarts and eat from cans of beenie weenies and vienna sausages. Maybe the outboard will feel better later on and start for you. Screw the world, who cares? At least let me raise my sails and set myself free. But then after awhile it occurs to you that when all things reliable are not (such as this here Evinrude), it begins to bother you. After all, when you have been reliable all your life, you expect the same out of your stuff. All other things like nature has a right to be unreliable, like the wind that has decided to go away. So there you sit wondering. Wondering what to do next.You have decided that if ever you get this pig motor going, you are gonna take it to the repair shop and get it fixed once and for all. Once your conviction for your plans settle you, you think back of how well this engine ran for the previous owner when he sold you this boat. Told you he just replaced the spark plugs and it was running gooooood! Yep, it sure was .... up to about a week ago. Spark plugs never go bad in just 1 month, right? Maybe if they were cheap ones, but then why would the previous owner do that? Could it be? Moments later, the cover on the engine is off and I am looking at the spark plugs. Both of them say they are AC plugs. Mmmm ... those are good major automotive brand plugs. Cheap but good. Wish I had brought a plug wrench. But later, the engine starts again. Spits and sputters me back to the marina slip where I am off on a mission to replace the plugs. Sure enough, the old plugs look fouled, but then, this is a two stroke and I wouldn't expect them to be in better shape. So I replace them with the same type of plug ... also AC brand.Motor purrs like a kitten. But then, inside of a month, same thing ... spit and sputter. West Marine runs an ad in their paper boasting their Marine grade plugs at 11 bucks each. This is the sale price because they are normally 12 bucks apiece. Begin wondering if there is a difference in Marine performance vs using an automotive alternative. The brand was Nippendenso which rang a bell. Wasn't that the name of the plug in my pressure washer? After checking, (a 9 horse Robin model EH25) used a Nippendenso plug. I tested the plug in my outboard and it fit with no interference with the piston and it ran, although the other plug was still an AC plug. Went to Auto Zone and purchased and unGodly number of them 12. Yes a dozen!Put a pair of those Nippendenso plugs in my Evinrude and stowed the rest of them with a plug wrench in the galley cabinet under the sink. That was over year back, and she still runs smooth!!!! Now here is the clincher. Paid only 14 bucks for the dozen plugs and still have 10 left sitting under the sink.Moral of this story?Yes ... there is a difference in Spark Plugs!Tom

 

[MrBill_FLL]

uhhhh. whats the heat range of them plugs?

FWIW, I always used NGK plugs in my outboards...and keep a spare pair aboard with a adjustable wrench. and some wet dry sandpaper, (and a water pump kit)... -but I like to be prepared..-is this the place you really want to try to save a few bucks???also fwiw, an old trick when selling a boat was to run 1 heat range hotter. so the plugs don't foul... 2 ranges hotter will burn a hole in the top of the piston, over time.-why dont you just get the carb rebuilt? its a maintenance item in my book, just like the impeller... 1x/yr whether it needs it or not...(& cheap compared to a new OB)

 

[ClownPilot]

Mr Bill

Thanks for that information. You know, I did check to see how those plugs were getting along ... they were uncommonly clean for a 2 stroke. I am a careful person and always measure my oil&gas mixtures to OEM. So now this may explain the performance issue. Don't know the heat range right now, but will find out this afternoon. I have a sneaking suspicion now that it may be a higher heat range that is giving me such good results!On my Evinrude, I have an external knob for adjusting the fuel mixture. Basically if I set it at about 1/5 of full she runs fine (In Florida) and doesn't take long to warm up. This motor is probably close to 20 years old now. Electronic ignition (9.9 Yacht Twin). I'm a fairly DIY guy, but I think carburetor rebuilding will have to be done at the marine dealer. By the way Bill, I did change the waterpump ... never again. LOL, the marine dealer gets that job next time.ThanksTom

 

[oldiesrocker2001]

That's right, mr. Bill,

I agree with you Bill, the NKG worked the best. for several years my little 2-stroke outboard only worked when i tested and rarely when I needed it. I once took the whole fuel system apart and cleaned it only to have it work well for only a few minutes back on the water. I also sandblasted the plug with a little home unit that I had for years. It finally took an embarrassing stall at the dock to make me start to think like a pit crew chief again and start looking at different heat ranges. Only needed one range hotter and and never had another problem...

 

[caguy]

Keep a can of Hot Shot for those stressful moments

If the motor still doesn't start, a hit of the ether will calm the nerves.

 

[MrBill_FLL]

my 1988 merc 9.8 still runs great

the carb kit is almost $90 and waterpump kit is about $60, and I do them every fall. I cannot afford to break down... my time is too valuable when I want to go sailing... ie., I spend a lot of $$ to get to the ramp... last thing I want is a break down when relaxing..Oh, Everyone ALWAYS mixes fuel stabilizer in their gas, RIGHT????(I use stabil, but evenrude 2+4 or similar works fine).Even with 100% gas, it would go bad in 4 months, and if you get ethonol, figure 2 months max...ob motor dealers love, bad fuel and old impellers... -btw, I have run 1 heat range hotter in a motor for a few years w/ no problems... (johnson 1985 235hp)... I also had to rev in neutral to burn off the carbon on merc 200, just before trying to get up and go... but those 6 pack carbs are a bear...

 

[Greg]

Motor problems

I rebuild outboards and many are run too rich. On small sailboats the engine is actually too big for the boat, so it never gets to run at anywhere near full throttle. On an old 2 cycle this is going to result in fouled plugs. If the mixture is too rich the plugs will foul, but if too lean, the engine will warm up faster, and run fine, except it will be running too hot. Better fouled plugs than a burnt out motor when you need it. Going up one heat range can help alot, when you don't get the engine up to rpms. Getting a lower pitched prop will give your motor more rpms, reduce the load on the engine, increase thrust, give better fuel economy, and also help reduce plug foulling. Most small outboards under 15HP were built to be used on a row boat. A 12' aluminum boat will get up on plane with these small engines and the prop they come with. Your sailboat will not. So you don't run them at a high enough speed (rpm) for the engine to blow out the crud it has accumulated durring all that less than half throttle use. This causes carbon to build up on the plugs and also in the exhaust system. Excess carbon in the exhaust system increases back pressure, reducing you available hp, and causing even more carbon build up in the cylinders (excess engine wear), along with reduced fuel economy. A carb rebuild is very easy. Just keep everything clean. Do measure the float height. It is mostly replacing the bowl gasket, cleaning out old varnish from the ports. A new needle and seat, for both the main jet and float bowl. Cleaning out the float bowl, and setting the float height. If the float has a hole in it replace that too. After that it's just a carb adjustment. OH, clean the flash supressor if it has one. Carb cleaner works there too.As for the amount and type of oil to use. Fallow the manufacturers reccomendations. The amount of oil is for lubing the bearrings. Better fouled plugs than a bearring going bad. If in doubt, use more oil. Better to smoke a little than burn a brearring or ring.

 

[ClownPilot]

Thanks Greg

Very good information. Between you and Mr. Bill, I feel as if I owe you boys a fee or something. I feel the best thing now is to check with my marine dealer up the street from where I live and see about whether he can order a shop manual for me. While I am at it, I will see about what the heat range is supposed to be on that motor and get the right NGK plug.Thanks againTom

 

[MrBill_FLL]

Greg, your Opinion on DeCarb spray?

What do you think of using a decarb type of spray?and any comments on fuel stabilizer and 10% ethonol? any prefered brands, or online sources for parts???

 

[Greg]

DeCarb

#1 Decarb, if it's really bad, a wire brush. If the engine is running but has an exhaust carbon problem try Sea Foam.#2 Stabil worked good, and will work good on winter fuel, but all the alcohol in the summer gas, you just have to keep fresh gas. Buy just what you think you need, pour the left over in the car. With 10 or so gallons of gas it won't even smoke.#3 For parts I search the internet most of the time. No prefference really. For out boards with low compression, I like Bosh spark plug. The titainium ones with 4 electrodes. About the same price as West Marines plugs, but burn oil alot better. Low compression will foul plugs too, it's usually caused by too much carbon in the cylinder from running too long at low rpm's. A common problem on small sail boats. Only real fix for this is new rings, after having the cylinder bored.#4 A lot of this work can be done at a lawn mower shop for less than an out board shop. Many of the bearrings, and seals can be had direct from Timken saving you a bundle. Small motor shops use this trick alot.