dreaco_99 0 Report post Posted May 29, 2002 I was wondering if it would be better for my engines ('75 and '66) to run a lead substitute with the gas. I use the same stuff with a cap of castor oil per tankfull in my Harley (also a '75) because it hasn't been rebuilt and doesn't have hardened or Incanel valves and seats. I know this "new fangled" unleaded and MTBE gas burns a bit hotter and doesn't have any lubricants like the old regular gas did way back when, so...is it a good idea or not? Share this post Link to post Share on other sites
HubbardRA 17 Report post Posted May 30, 2002 Most one cylinder engines were originally designed to run on unleaded gas. A lead substitute is not really necessary, especially with the low compression ratios that they run. You will not have a "ping" or detonation problem, and you should not be burning valves unless you are running your carb mixture extremely lean. Rod H. Share this post Link to post Share on other sites
Kent 434 Report post Posted May 30, 2002 And they con't carbon up nearly as bad running unleaded gas -- the old "remove the head and clean the carbon at 100 hours" service in the old Briggs owners manuals is no longer necessary.... Share this post Link to post Share on other sites
CleanBee 0 Report post Posted May 30, 2002 I seem to recall hearing that the valve seats may burn out if they are not hardened and unleaded gas is used. I was told years ago from my Dad that both the 9 and 10 hp briggs motors used on there B-10's have hardened valve seats and are ok with unleaded gas. I also recall hearing that if you do have non-hardened seats that running your engine with a slightly richer fuel setting, or jetted, will help prolong the life of valve seats. I know with motors in general, richer fuel settings and slightly less advanced ignition allows motors to run cooler, but also inhibit performance slightly. Dan Share this post Link to post Share on other sites
JonetteP 0 Report post Posted May 30, 2002 Hi Dreaco, I do not have the knowledge at this time to properly answer you question. However, I do know that my father used vegetable oil to lubricate some of the first polaris race engines he made. He made the rings from spring brass, and mixed in the gasoline a combination of regular 2- cycle oil, vegetable oil and a number of other products to make the rings last. Neal Share this post Link to post Share on other sites