Honda 40 with Burnt Plugs

[Navigator]

I have a strange question...<br /><br />My current setup allows the engine to run right at the redline when the boat is lightly loaded. (normal load drops the rpms about 100 or so) We put in a new set of plugs the other day as routine maintenance and have since put about 10 or so hours on them. We pulled them out tonight and found that they appear to be pretty burnt looking. Definitely not normal.<br /><br />My question... could the high RPM be burning the plugs up? The engine is otherwise running great. (I am in the process of changing the prop out to bring the RPM's down a bit)<br /><br />Has anyone ever seen this before? Should I swith to a colder running plug?<br /><br />Nav

 

[Skinnywater]

Re: Honda 40 with Burnt Plugs

Nav, <br />My BF50jet runs at WOT for hours at a time or idle for hours at a time, hardly anything in between.<br />Since it's a jet I have to run WOT for speed and since I back troll in a 3-4mph current (jets don't have a true nuetral position), my nozzle gate is adjusted that idle speed is perfect.<br /><br />The only running problem I've had with my '02 Honda, now at 380 hrs. was #2 spark plug failed.<br />This was my fault since somehow I neglected to replace them at the recommended 200 hour service.<br />I checked them pretty regular and they always looked the same, in good condition.<br />At almost a perfect 300 hrs. the plug failed.<br />It wasn't burnt as you'd expect at the tip of the electrode, but up inside the tips insulator, as it fell against the ground tab.<br /><br />My plugs never looked burnt. Always very clean and free of deposits.<br />It came from the factory with DR7EA NGK's and that's what went back in gaped at .024in.

 

[BF130]

Re: Honda 40 with Burnt Plugs

Navigator, double check that you're using the correct plugs and also double check gap.

 

[Navigator]

Re: Honda 40 with Burnt Plugs

I know the gap is correct. I'll have to double check the plug number. Its possible the Honda Dealer screwed up and gave me the wrong plugs. <br /><br />Nav

 

[Skinnywater]

Re: Honda 40 with Burnt Plugs

NGK-DR7EA<br />NipponDenso-X22ESR-U<br />Gap for either- 0.6-0.7mm (0.024-0.028in.)