Nissan 5hp Starting Issues

[ziton]

Re: Nissan 5hp Starting Issues

Isn't this about half the proper psi?
I have a 15 rude that does the same thing.
50 psi on each cyl.
Scrubbed the rings I guess.

. Tested it COLD and only got 40 psi.


Redid the compression test hot and got 50psi.

 

[rythmman]

Re: Nissan 5hp Starting Issues

This is what I got from Tohatsu:
50-55 psi, with decompression device working
115-120 psi, with decompression device disengaged

 

[rythmman]

Re: Nissan 5hp Starting Issues

Still looking for an answer to the stuttering problem. The motor also dies if I accelerate quickly.

 

[pvanv]

Re: Nissan 5hp Starting Issues

This is what I got from Tohatsu:
50-55 psi, with decompression device working
115-120 psi, with decompression device disengaged

Decompression device on a 1-lung 5-hp 4-stroke?

 

[TOHATSU GURU]

Re: Nissan 5hp Starting Issues

I would revisit the carburetor again....Sometimes whatever is lodged inside of one cannot be removed and you have to replace it. I would try to borrow one locally from someone with the same engine or give up and take it into a dealer.

 

[rythmman]

Re: Nissan 5hp Starting Issues

I am begining to feel that the easiest way to solve these problems is to swop with parts from a good motor I now need to OFTEN remove the spark plug , clean it and replace, as there is excess gas on the plug. How do I determine if the spark is weak or carb is delivering too much gas?

 

[TOHATSU GURU]

Re: Nissan 5hp Starting Issues

By using your service manual, to correctly test the ignition parts, you can eliminate them as the problem and move on to mechanical or fuel system troubleshooting.

Lets revisit what I told you earlier.

"You don't know what you are doing. Its that simple."

And I will add this.

Desire and determination to solve a problem does not equate to the ability to do so. There is a skill set involved that comes from technical training, innate skill, experience and last, but not least, luck. I applaud your determination, but....

 

[rythmman]

Re: Nissan 5hp Starting Issues

I have read many threads and OFTEN people have gotten incorrect resistance values for the electronic parts, but that has not been the problem. I am determined to solve this...if I can repair Ferraris , I'm sure I can repair this!

 

[TOHATSU GURU]

Re: Nissan 5hp Starting Issues

I can't repair a Ferrari...But, I can fix this brand of outboard. I know my limitations

 

[rythmman]

Re: Nissan 5hp Starting Issues

You wouldn't want to!!! LOL

 

[rythmman]

Re: Nissan 5hp Starting Issues

Which is a more common part to replace; exciter coil or ignition coil?

 

[TOHATSU GURU]

Re: Nissan 5hp Starting Issues

Niether one...You have to test the ignition parts using the service manual. The values are contained within.

 

[pvanv]

Re: Nissan 5hp Starting Issues

Agreed. Verify resistance values on ignition components, verify carb is not flooding, and go from there. As I mentioned earlier, poor spark is rare on these, but carb problems are not unheard of. They use tiny amounts of fuel, and a weeping needle valve can overfill the bowl, causing flooding.

 

[rythmman]

Re: Nissan 5hp Starting Issues

Is the spark visible under normal outdoor light or only in a dark room?

 

[TOHATSU GURU]

Re: Nissan 5hp Starting Issues

Low light conditions would be easier on you.

 

[rythmman]

Re: Nissan 5hp Starting Issues

Have a spark under low light (eve), but every 5th revolution there is none. The mystery continues....

 

[pvanv]

Re: Nissan 5hp Starting Issues

Time to drag out the Factory service manual and a good analog ohmmeter. Or better yet, one with DVA capability. Reading the ignition coil input with a DVA (and having impedance numbers) will help you diagnose the entire ignition system. Keep in mind that these fire on both compression and exhaust strokes (every time the piston comes up).

 

[rythmman]

Re: Nissan 5hp Starting Issues

I built a dva and think the exciter coil is faulty. The reisitor reading, in the manual, for the ignition coil gives 3000-4400 ohms. I have 6500 ohms. We did discuss this before, but want to check that my figure is acceptable or should I replace it too?

 

[pvanv]

Re: Nissan 5hp Starting Issues

Of course, a DVA is not needed to measure impedances. Any good DC ohmmeter will give correct readings. But... it does sound as though the ignition coil is a little out of tolerance. Keep in mind that listings for coil impedances are typically +/- 20%... so, yes, the ignition coil is a bit on the high side. Probably OK though. Two bad ignition components on a single problem is unusual, unless one bit blows, taking out others... what is the impedance of the exciter coil?

 

[rythmman]

Re: Nissan 5hp Starting Issues

I was using my dva to check voltage of the exciter coil as I cranked the motor. There is a post here about it and the voltage was low, so I have ordered a new one and hope that it will be solved. Stay tuned.