15hp nissan tries to run backwards

[OQMJr]

i recently got a 92 nissan 15hp outboard, with electric start. wasnt getting spark so replaced cd with an aftermarket cdi one with the built in coil. now i am getting good hot spark on both cylinders, but when i try to start it, it turns the right direction then kicks and starts running roughly counter clockwise. i looked around on the web, including this site, and saw that it was most likely timing being to far advanced, so i checked timing and kept retarding it, retarded it all the way and it still tries to run reversed. i pulled flywheel there are four magnets, they look good and are secure. everything underneath looks good, but i was wondering if there are four magnets then the trigger coil tries to make the cylinders fire at tdc and at full stroke and inbetween, because both plugs fire simoultaneously(bad spelling im sure) was wondering if there was anyone who could shed some light on this for me.

 

[pvanv]

Re: 15hp nissan tries to run backwards

Year means nothing; Model is important. Assuming you have a 15B2.

There is only one trigger coil, and only one exciter coil. There is also an optional alternator coil, which would be standard on electric-start models. The exciter charges the CD, and the trigger fires the CD. Yes, both cylinders fire at the same time, both compression and exhaust. Static Timing is fixed by the magneto key (woodruff key for the flywheel), and is not "adjustable". The coil plate is advanced by operating the throttle. That plate then in turn opens the carb via a cam segment. The carb must be synced to the ignition for proper WOT operation, and correct acceleration.

Is your magneto key partially sheared off ?

What is the timing (in degrees) with the throttle closed ?

Did your aftermarket CD have a wiring diagram ? You may have the trigger and exciters reversed, which could throw timing WAY off.

 

[OQMJr]

Re: 15hp nissan tries to run backwards

the woodruff key is in good shape, it is an ns15b2, the wiring is correct via cd manufacturers diagram. the flywheel is part of an aftermarket kit for elecrtric start or atleast it appears to be, can't find any definitive timing marks on it, but i set it tdc on the top cylinderr and lined up the timing plate so the trigger coil just hit the gap between magnets whenthrottle closed and that is where timing was initailly at so i scribed a mark into the flywheel.. but 've tried the full range of adjustment through the timing plate linkage and it still tries to kick backwards, the motor had sat for a couple of years before i got it. I've done the resistance test on the trigger and its within specs, but im wondering if it might be bad anyways. will double check all wiring today. another quick question on it, could it be detonating by compression and should i try a higher octane gasoline?

 

[JB]

Re: 15hp nissan tries to run backwards

Have you tried switching the spark plug wires back where they belong??

 

[TOHATSU GURU]

Re: 15hp nissan tries to run backwards

I think I would throw away the aftermarket CD and put on the OEM CD, which is available.

 

[OQMJr]

Re: 15hp nissan tries to run backwards

i found an oem cd at a local marine junk yard yesterday, installed it and still no improvement. but atleast extra parts are always nice to have. they didnt have the timing plate assembly, but i know an automotive junkyard that has some small old motors, gonna give them a try today and see if they have one with a timing base that will work. i think the trigger might be shorting internally. i rechecked the resistance yesterday and its at 57 when the specs call for between 30-45. any ideas or suggestions are greatly appreciated, at the moment all i have is about a 400 dollar longshaft anchor.

 

[pvanv]

Re: 15hp nissan tries to run backwards

Are you testing resistance with a good quality ANALOG meter? If not, your numbers are unreliable.

 

[OQMJr]

Re: 15hp nissan tries to run backwards

the one i use is made by cdi and is digital with the analog bar under the digital readout. should i get a regular needle style analog?

 

[pvanv]

Re: 15hp nissan tries to run backwards

Yes. It must be analog, with a battery voltage of 3v or less. Digital meters do not load the circuit adequately, and will give inaccurate readings. Tohatsu sells one: Analog DVA/Multimeter to check AC/DC voltage, Ohms readings/resistance, and voltage outputs using DVA scale. A must have for proper electical testing. Can be used on any outboard. Part # 99998D530M $124.32

 

[OQMJr]

Re: 15hp nissan tries to run backwards

borrowed a meter from my nieghbor, and took the readings again on the trigger, resistance is at 53 on his. still plan on ordering my own meter this week. the specs call for between 30 and 46.

 

[K38Bob]

Re: 15hp nissan tries to run backwards

Year means nothing; Model is important. Assuming you have a 15B2.

There is only one trigger coil, and only one exciter coil. There is also an optional alternator coil, which would be standard on electric-start models. The exciter charges the CD, and the trigger fires the CD. Yes, both cylinders fire at the same time, both compression and exhaust. Static Timing is fixed by the magneto key (woodruff key for the flywheel), and is not "adjustable". The coil plate is advanced by operating the throttle. That plate then in turn opens the carb via a cam segment. The carb must be synced to the ignition for proper WOT operation, and correct acceleration.

Is your magneto key partially sheared off ?

What is the timing (in degrees) with the throttle closed ?

Did your aftermarket CD have a wiring diagram ? You may have the trigger and exciters reversed, which could throw timing WAY off.

Its a 2 cylinder engine but both power strokes occur simultaneously? Doesn't that defeat a big benefit of 2 cylinders?
Is this (and the 15hp) basically the 5sb motor with a cloned extra cylinder?
thanks
bob

 

[TOHATSU GURU]

Re: 15hp nissan tries to run backwards

No, no and no.

 

[pvanv]

Re: 15hp nissan tries to run backwards

Its a 2 cylinder engine but both power strokes occur simultaneously? Doesn't that defeat a big benefit of 2 cylinders?
Is this (and the 15hp) basically the 5sb motor with a cloned extra cylinder?
thanks
bob

Elvin is 100% right. the cylinders fire alternately. There is an "extra, wasted" spark on the exhaust stroke, which allows use of the siamese ignition coil. The motor produces power each 180 degrees of crank rotation, once each 360 degrees on each cylinder, but staggered bu 1/2 revolution. The 15 is nothing like the 5.