I have a Merc 9.9 electric start outboard. Starts hard. Switched to non ethanol gas and things improved. Am using 87 octane. Should I go higher? Plugs have blue spark but not a dark electric blue.Just how much spark do you need to start a 10 horse?
small outboards and octane. How much?
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Just a spark is required. As long as the engine's getting fuel and spark and has compression it has to run. It sounds like you have good spark, so I'd suspect, off the top of my head, that you may have a dirty carb or your fuel is stale. Have you tried ether when it's hard to start? If it starts good on ether, then I'd really suspect a fuel or fuel system problem.
I keep ether around for starting my manual-start generator in the winter. It keeps my arm from falling off!
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most of the older 2 strokes(1970's,80's,90's) were built to run on 87-89 octane and unless you are bumping the compression or messing with the timing you should stay with the manufacturers recommended octane. if you have the owners manual for that motor have a look and see what it says.
just remember in a 2-stroke not enough octane and you will get detonation (pre-ignition) which is hard to detect in a 2-stroke and very bad for your motor,,,,to much octane and you will start to lose power and your motor will not run as well!!
hard starting could be from iproperly adjusted choke circuit,bad compression,bad reed valves,ect,,so if you could give us a litle more info it would help
just remember in a 2-stroke not enough octane and you will get detonation (pre-ignition) which is hard to detect in a 2-stroke and very bad for your motor,,,,to much octane and you will start to lose power and your motor will not run as well!!
hard starting could be from iproperly adjusted choke circuit,bad compression,bad reed valves,ect,,so if you could give us a litle more info it would help
I was advised once not to use starting fluid to start an outboard. I use cheap Family Dollar aeresol lubricant (propellant is flammable) works fine. Motor Starts ok when sprayed with lube and is ok when engine is warm. Next day cold engine same problem. Do not know how to check or repair fuel delivery. How does one check for proper air/gas mixture to cylinder? Motor wasn"t used for some time. Is it possible carb varnished up from idleness? Have never tried to clean carb with an additive,did not know what to use that would not hurt engine.
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Try using some seaform. You can get it at NAPA auto parts.
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oka start hard do not use starting fluid!! wd40 will work you probably have a varnished carbs it only takes two weeks for the fuel of our time in a carb to varnish. i have seen this happen time and time again. you can do one of two things the first one i suggest is drain the carb of all fuel than fill the choke bowl with a carb cleaner and let sit overnight. next day redrain the carb cleaner and fill with fresh fuel and start engine up and run while engine is running bring it to a fast idle and spray with carb cleaner slowly about 1/2 a can after that spray rest of can threw carb to kill engine let sit 15 minutes. than restart engine may be hard to start but once it start let it run till they heavy smoking has quit. shot engine down change the spark plugs and restart and run for a few minutes. if this does not help you will need to rebuild the carb and do a sink and link of the carb and linkage.
while your at it you might want to change the water pump out
hopes this help. and yes this is not a trick i have been working on outboards for 10 years and i am a certified mercury tech
while your at it you might want to change the water pump out
hopes this help. and yes this is not a trick i have been working on outboards for 10 years and i am a certified mercury tech
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only do it for friends anymore. it was a hobby of mine but i took it to be a livley hood and it got to be a hassle could not even take the family to the lake without being buged to work on someones boat. now i have the itch back but want to keep it simple and small so i do it part time on my own
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Two things:
1) I put a little stabil in the fuel any time I'm not going to be running the boat right away. Early spring and late fall when I'm never sure when I'll get back out again I always add some stabil. It's worth the money to avoid gunked up injectors or carbs.
2) There is a huge myth perpetrated by gasoline companies that higher octane fuel is better. It isn't unless you have an engine designed for it. Higher octane fuel is actually LESS combustable than low octane fuel. You read that, less combustable. The reason you run a higher octane fuel is if you have a high compression engine. What you don't want happening is pre-ignition of the fuel due to pressure and heat before the spark timing. (Basically your engine is working like a diesel and the fuel is igniting because of the heat and pressure and not because of the spark.) You use a high octane fuel because the high-octane is less combustable, and therefore it won't pre-ignite. That makes sure your combustion occurs due to the spark.
If you're getting pre-ignition before the spark occurs you'll experience engine knock which can cause severe damage. Power and responsiveness is also crappy.
For 95% of the vehicles sold in the US though, 87 octane is all you need. They do tend to use more ethanol and better detergents in higher octane gas, but it's not worth the 7-10 cents a gallon to get midgrade or twice that for premium.
The vehicles you do want to run higher octane fuel in are motorcyles and dirtbikes, snowmobiles, and anything else running a high compression ratio to get the maximum power out of a little bitty power-plant. Most boat motors do not need it. If you find your motor is running rough though and you already know it's not a lean/rich problem, you can always try going up a grade of fuel. Normally though, it's just a waste of money.
1) I put a little stabil in the fuel any time I'm not going to be running the boat right away. Early spring and late fall when I'm never sure when I'll get back out again I always add some stabil. It's worth the money to avoid gunked up injectors or carbs.
2) There is a huge myth perpetrated by gasoline companies that higher octane fuel is better. It isn't unless you have an engine designed for it. Higher octane fuel is actually LESS combustable than low octane fuel. You read that, less combustable. The reason you run a higher octane fuel is if you have a high compression engine. What you don't want happening is pre-ignition of the fuel due to pressure and heat before the spark timing. (Basically your engine is working like a diesel and the fuel is igniting because of the heat and pressure and not because of the spark.) You use a high octane fuel because the high-octane is less combustable, and therefore it won't pre-ignite. That makes sure your combustion occurs due to the spark.
If you're getting pre-ignition before the spark occurs you'll experience engine knock which can cause severe damage. Power and responsiveness is also crappy.
For 95% of the vehicles sold in the US though, 87 octane is all you need. They do tend to use more ethanol and better detergents in higher octane gas, but it's not worth the 7-10 cents a gallon to get midgrade or twice that for premium.
The vehicles you do want to run higher octane fuel in are motorcyles and dirtbikes, snowmobiles, and anything else running a high compression ratio to get the maximum power out of a little bitty power-plant. Most boat motors do not need it. If you find your motor is running rough though and you already know it's not a lean/rich problem, you can always try going up a grade of fuel. Normally though, it's just a waste of money.
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I buy 89 octane fuel for my 90 hp Evinrude Ficht. I've been told gas loses octane after a while. 31 gallons is far more than I can burn in a couple weeks. I'm a weekend boater. Because my gas is never fresh, I always put sta-bil in at purchase. During the Summer months, I keep the tank half full. Am I wrong in buying mid-grade?
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TONGA wrote
I guess I should have spelled it out a little better,,,,
If you wan't to get the max power from your 2-stroke outboard you wan't to keep the octane just above detonation,maybee a point or 2 over just to stay safe because the consistency from station to station ( light detonation is hard to hear in a 2-stroke)
higher octane fuels have a slower burn rate, thus preventing detonation, but a 2-cycle engine has a short duration time whereby the piston, which acts as a valve, has ignition, then passes the exhaust port, and if the gases burn too slow you can loose the push of the piston by the unburned charge escaping out the port when the burn should have already been over.
so you see if you crank the octane way up you will get les power from your motor,,,if you don't belive me just fill your tank with 104 race fuel and see how bad it runs
I guess I should have spelled it out a little better,,,,
If you wan't to get the max power from your 2-stroke outboard you wan't to keep the octane just above detonation,maybee a point or 2 over just to stay safe because the consistency from station to station ( light detonation is hard to hear in a 2-stroke)
higher octane fuels have a slower burn rate, thus preventing detonation, but a 2-cycle engine has a short duration time whereby the piston, which acts as a valve, has ignition, then passes the exhaust port, and if the gases burn too slow you can loose the push of the piston by the unburned charge escaping out the port when the burn should have already been over.
so you see if you crank the octane way up you will get les power from your motor,,,if you don't belive me just fill your tank with 104 race fuel and see how bad it runs
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87 to 89 octane is all you need on your small rigg if you want the expensive gas my wallet is open just give me the extra money.
you work on alot of motors tango? you sound like you pretty much know what ur talking about. so far i have to pretty much agree with everything you have said
you work on alot of motors tango? you sound like you pretty much know what ur talking about. so far i have to pretty much agree with everything you have said
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Great info guys Thanx.
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I had a Mercury 6hp about a '77 or so and hated it. I used it for duck hunting. If it was below 50 degrees it wouldn't start. I had to keep the motor in the house all night, then move into a warm truck. That was the ONLY way it would start. Then I bought an old '75 Johnson 9 1/2 hp, it started second pull every time. Even below freezing temps. I'll never buy another Mercury!! I run 87 octane in my 9 1/2 and my 40 hp. Never a problem.
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