Nissan 30hp not reaching desired rpm range

[dgt69]

Used my boat yesterday and it ran fine until I decided to head back to the boat ramp. It would not power up and had to limp back at 8mph. Do not have a tach but I'm guessing it would not get above 2500rpm. It does not like to start with the trim up either. Sometimes I will have to half choke it if I have had the trim up. I think a piece of dirt got stuck in one of the carbs. Any suggestions? Thanks.

 

[Sea Rider]

Re: Nissan 30hp not reaching desired rpm range

Is it a 2 or 4 stroker, how old is it ? current poduction 2 strokes are single carbed.

 

[dgt69]

Re: Nissan 30hp not reaching desired rpm range

Its a 2003 4 stroke 3cyl. My guess is that a piece of junk got stuck in one of the jets or floats are stuck.

 

[Sea Rider]

Re: Nissan 30hp not reaching desired rpm range

That's what I hate about counting with a carb for each cylinder that's why preffer 2 cylinder single carbed engines. Start checking carbs...

Happy Boating

 

[pvanv]

Re: Nissan 30hp not reaching desired rpm range

You could have something as simple as water in the fuel. The 30A carb setup is a wee bit complex, so run the carbs out, religiously, at the end of every day, as you don't want to be cleaning carbs all the time. If you are running with incorrect fuel mix (check plug color), you may want to have a dealer look at it. Running one cylinder too lean could possibly burn a piston.

 

[fishhead1954]

Re: Nissan 30hp not reaching desired rpm range

I have a 2003 Nissan 4 stroke 30HP and it did that about 3 years ago. After plenty of head scratching I pulled the plugs and looked at them. They looked good but since I had them out anyway I put in new Champion plugs, (All I Could Find At The Time). It has been running great since. Hope that helps.

 

[pvanv]

Re: Nissan 30hp not reaching desired rpm range

That motor will always run best with NGK DCPR6E plugs.

 

[dgt69]

Re: Nissan 30hp not reaching desired rpm range

I pulled the plugs yesterday and they look pretty good. The gas tank is only 4 months old and I use nonethanol. I will try changing the fuel filter and take it from there. Thanks.

 

[dgt69]

Re: Nissan 30hp not reaching desired rpm range

Its a 4 stroke so no fuel mix. Plugs look pretty good. I use nonethanol and the tank is about 4 months old. I am going to try changing the fuel filter and see how it runs. Thanks.

 

[pvanv]

Re: Nissan 30hp not reaching desired rpm range

It does sound like it is starving for fuel. So verify the fuel system... all the way from the tank pickup to the carbs. A new filter won't hurt. If the carbs weren't run dry at the end of every day, expect a 3-carb cleaning to be needed.