Re: merc 500 thunderbolt
Just convert it over to regular marine fuel line, with hose clamps at the ends (same as OMC does it). You can find fittings that'll thread in at any NAPA or other serious auto parts store - they are a very common thread. Sometimes you have to put a couple together to get what you want (right thread size on one end, right tube size on the other). <br /><br />I am mostly an OMC V4 fan, but I have owned 5 500s and will respectfully disagree with some other posters - these are good motors. They will idle extremely well, yet produce good top end, so great ski/fishing combo. Merc made them for what 30 years, probably the longest-lasting design out there, lots of people racing them still. They do have (as you will find) some areas that are unnecessarily hard to work on (e.g., draining the carbs on the 1970-74 500s is a pain in the ***). <br /><br />Some tips. Do replace the impeller - if it goes you will have no warning until the engine seizes, and this is one area where Mercs are very easy to work on, easier than OMCs. Clean the carbs, then be SURE you don't run old gas after that. Run fresh gas, 50:1 oil (not MORE oil than that), and put a filter on the inlet fuel line. Check the wide-open-throttle timing - it's real easy to adjust the WOT timing stop, by the way. Those engines like to wind up a bit, so prop it so that, when you're alone in the boat (light load), you're at around 6000 rpm. If you just want to get out on the water, don't run it at sustained WOT until you check do all the above. There is no thermostat on these engines, so if you're cooling correctly, the exhaust plate cover (big plate under the engine band, covering most of the port-side rear of the motor) should be just a hair warmer than the lake water you're running in.
