1992 Nissan 18hp Outboard Starting Problem

NissanUser18

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Jun 9, 2013
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Hey, I used my boat yesterday for about 3 - 4 hours without any problems even turned it off and turned it back on. But I came to my dock today to find out it didn't start, so i ran up to the store got new spark plugs(the same ones as old but new) I replaced all of the fuses. But It still does the same thing I also took the spark plugs out and let the engine dry out for about 5 - 6 hours and then I put the spark plugs back in and it didn't start. The spark plugs aren't getting any sparks and they also feel dry after I try starting it a few times.

- Please help thx.
 

pvanv

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Apr 20, 2008
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6,500
Re: 1992 Nissan 18hp Outboard Starting Problem

Could be almost anything. What is your exact model? How did you check for spark? Is the stop clip attached? If electric start, there is only one fuse. What fuses did you change, and why? If no spark, and the rest is OK, you would have wet plugs. What is the actual symptom? Does it crank? Crank and not fire? Sputter?
 

NissanUser18

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Jun 9, 2013
Messages
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Re: 1992 Nissan 18hp Outboard Starting Problem

@pvanv

It does crank, but it doesn't fire up. I disconnected the kill switch/safety switch and tried to start it and it still didn't turn over. I checked for spark by unscrewing each spark plug and barely touching it on the wire to see if it sparks. The Old plugs were really wet, after we put new ones in it didn't get them wet as much as the old. So I put the old ones back in and they weren't getting wet. Every time we crank it gas is coming out some where and is turning the water to a rainbow-ish color we know its getting gas. I also cannot pin-point the model because the registration is at my cottage. And the safety switch is in.
 

TOHATSU GURU

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Jul 22, 2004
Messages
6,164
Re: 1992 Nissan 18hp Outboard Starting Problem

If the spark plugs do not have any spark when you ground them out, you will have to run the ignition system checks in the service manual to see which part has failed.
 

pvanv

Admiral
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Apr 20, 2008
Messages
6,500
Re: 1992 Nissan 18hp Outboard Starting Problem

If you are spilling raw fuel outside the motor (and the fuel lines are properly connected), you are overfilling the carb and flooding out the vent. That would probably be a stuck float/needle/seat.

OTOH, if the carb is working OK and there is no spark, you could get gas out of the exhaust. If you unplugged the brown wire from the kill switch, that takes the switch out of the picture. "Barely touching" the plug to the wire will not tell you whether you have spark. You would need to ground the plug threads, attach the plug wire, and then test... or use a spark tester.

The Factory service manual, available from any dealer (including Elvin and me, and others on this forum), details the procedure to test the ignition system. Hint: you must use a good analog (not digital) ohm meter, with a battery of 3v or less to test the ignition components.

Based on the size, it must be either an NSF18B or NSF18B2.

The correct Factory service manual is:
SERVICE MANUAL - TOHATSU - 9.9/15/18 A&B 4STR
Covers 9.9hp, 15hp, 18hp "A" & "B" 4-stroke models
Part # 003-21041-0
$40.00
 
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