AussieSteve
Active Member
I started to post this in '2-Stroke Engines', but it's probably relevant to both types of engine.
This isn't so much a problem as a general theory question.
A couple of weeks ago, I fitted a high compression head, so went up to about 98 octane fuel. Good combustion, no pinging, plug a light tan colour.
Temporarily, I've re-fitted the stock head, but I'm still running the same fuel.
The plug runs much colder, (black), than it did before the hi-comp head was fitted. It used to be tan, the same as with the high-comp head. (In fact, with the hi-comp head, an NGK B6HS burns pretty nicely.) The only change with the stock head is the fuel. (I added 8ml/litre Nulon Pro Octane Booster to standard unleaded, 91 octane in this country.)
My plug is an NGK B5HS - usually hot enough for these engines.
As I said, it's not really a problem because in a week or two I'll have the hi-comp, (Rock Solid Engines billet aluminium), head back on.
I'm just interested.
... Steve
This isn't so much a problem as a general theory question.
A couple of weeks ago, I fitted a high compression head, so went up to about 98 octane fuel. Good combustion, no pinging, plug a light tan colour.
Temporarily, I've re-fitted the stock head, but I'm still running the same fuel.
The plug runs much colder, (black), than it did before the hi-comp head was fitted. It used to be tan, the same as with the high-comp head. (In fact, with the hi-comp head, an NGK B6HS burns pretty nicely.) The only change with the stock head is the fuel. (I added 8ml/litre Nulon Pro Octane Booster to standard unleaded, 91 octane in this country.)
My plug is an NGK B5HS - usually hot enough for these engines.
As I said, it's not really a problem because in a week or two I'll have the hi-comp, (Rock Solid Engines billet aluminium), head back on.
I'm just interested.
... Steve