Sick 5 hp Nissan (MODEL NS5B) 1998

Joined
Dec 20, 2003
Messages
10
I have a problem with rough running (at lower speed) and a miss at higher speed operation. I checked/ cleaned the carb. and changed the spark plug (NGK BPR7HS-10). I adjusted the pilot screw (on the carb.) about 1 turn out and got a smoother idle, but I still have the miss when the motor is under load higher rpm's).<br /><br />The motor was given to me by a fellow who had it stored on the back of his sailboat and hardly ever used. He bought it for his hard dinghy and found it was too much motor for the boat.<br /><br />I suspect I might have a faulty electronic system but don't know where to start. I bought a shop manual for NISSAN but it doesn't cover the 5 hp very well.<br /><br />Any help welcome.
 

45_red

Petty Officer 2nd Class
Joined
Jan 22, 2003
Messages
173
Re: Sick 5 hp Nissan (MODEL NS5B) 1998

If it starts easily, I'd figure you still have a fuel problem.Is the plug wet after running? What if any effect does the choke have? Does the bulb firm up?
 

bob58

Petty Officer 2nd Class
Joined
Sep 27, 2003
Messages
114
Re: Sick 5 hp Nissan (MODEL NS5B) 1998

Was this occuring prior to plug replacement?<br />Was the carb blown out real well after soaking in cleaning solution?<br />Did you gap the plug at .9mm to 1mm?<br />This is an internal tank engine so is the gas fresh or has it been in the tank for some time?<br />Is the mix 50/1 with TCW3 rated oil?<br />Is there water in the fuel?<br />Is the tell tail squirting a good stream of water?<br />Is the tank vent open and working?
 
Joined
Dec 20, 2003
Messages
10
Re: Sick 5 hp Nissan (MODEL NS5B) 1998

I have completely checked out the fuel system. <br /><br />According the to manuel it would be possibly <br />1) Ignition Coil<br />2) Pulser Coil<br />3) Exciter Coil<br />4) CDI unit<br /><br />The manuel comments that sometimes with the Pulser Coil the engine will run fine at one speed and miss at a different RPM.<br /><br />The problem I am having is that the wiring diagram in the manuel is very unclear about the 5 hp electronics. <br /><br />Anyone with knowledge about this particular motor, your input is welcome.
 

bob58

Petty Officer 2nd Class
Joined
Sep 27, 2003
Messages
114
Re: Sick 5 hp Nissan (MODEL NS5B) 1998

You can find your wiring diagram on page 38 HERE <br />You will need Acrobat Reader to view and it is a free download if you don't have it on your puter.<br /><br />Have the questions I posed above all been checked and eliminated as possible causes?<br />The reason I ask is Nissan points to these in there trouble shooting section!
 
Joined
Dec 20, 2003
Messages
10
Re: Sick 5 hp Nissan (MODEL NS5B) 1998

Thanks for the link to the engine manual!<br /><br />As is turns out the problem wasen't in the powerhead at all.<br /><br /> The clutch was slipping. I took it to a dealer/service rep and they wanted $430.00 to repair the gearcase!<br /><br /> So, I took it home and opened the gearcase and reversed the clutch and filed the ears so that they would be square then put it back together. I adjusted the shift rod clamp to be sure the forward gear was fully engaged when the shift lever was in forward. I then went to autozone and bought a quart of GL-5 #80-#90 synthetic gear lubricant for 5 bucks . Took the motor out to the lake and ran it HARD for about 2 hours. Problem solved. Cost 5 bucks.
 
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