Nissan 15hp 2001 missfire after cruising

[drpots]

I have a 2001 Nissan 15hp 4 stroke that after cruising for approx 15 mins or more will miss fire and run rough if you back off the throttle and try to re-throttle. If you turn off the engine and immediately restart it is fine, until you back off the throttle again. It's almost like it is only firing on one cyl after you back off the throttle.

Any ideas, it makes negotiating waves difficult.

Thanks

 

[pvanv]

Re: Nissan 15hp 2001 missfire after cruising

Could be a lot of things. I assume you have an NS15B2, right? You can check to see whether the plugs are fouled, indicating a possible flooding condition. Is the fuel fresh? If gas was allowed to sit in the carb for a couple of weeks, the carb may need a good cleaning.

 

[TOHATSU GURU]

Re: Nissan 15hp 2001 missfire after cruising

Could be going into protection mode. So, you need to take it into a dealer who will then test the CD module and the other ignition parts as well as go over the fuel system.

 

[pvanv]

Re: Nissan 15hp 2001 missfire after cruising

Very true. The ESG could be engaging prematurely after it gets hot enough... the CD could be failing when warm... as I noted, could be a lot of things.

 

[drpots]

Re: Nissan 15hp 2001 missfire after cruising

Well, thanks for the ideas. It seemed to me that it is more a electronic issue rather and anything else and probably management related, hence the 'reset' through a restart. But I wasn't sure if these engines were that technical.

 

[pvanv]

Re: Nissan 15hp 2001 missfire after cruising

Your motor has an ESG (electronic speed governor) that prevents over-RPM. It's supposed to kick in at about 6250 RPM. When engaged, it staggers the ignition, preventing you from running at speeds that would cause the motor to self-destruct (such as if you have a prop with too low a pitch). If the electronic control (internal to the CD) is failing when warm, the ESG could be engaging, leading to your condition. Diagnosis can determine whether that's the case.