Altitude Re-Jet Help Needed

Howdy ,

1997 Merc 60 hp ELHPTO 0G581911 purchased in Colorado/WME-45 Carb

Thanks for looking , I'm no dummy but in no mechanic either ...so please feel free to chime in .... the short of it lol ...lived in Colorado for 14 years , had the boat/motor 13 of them , previous owner was a native , he ran the motor there for years , motor ran flawless for me the entire time. Fast forward , I move back home , total altitude difference of like 4700 ft . Specs called for minor high speed jet differences.

I pulled the carbs and they were standard .062 jets ...so that leads me to think the previous owner had to have made altitude corrections by running leaner and a prop pitch change , standard is a 9 pitch , I had a 12 pitch .

Please correct me if I'm wrong , those are the only three places you can really make corrections for altitude on , jet , prop, lean carb?

I have everything back to the standard for my altitude and I'm going to run the motor but I have no idea how to tell if its running lean and I don't want to burn her up if my train of thought is correct .

I would think temp is one thing to watch out for so I installed a mini temp/hour meter , any other things I should look out for as far things that aren't right , high rpm maybe ? Make sure I dont go over max ( 5500) and see how it runs compared to the way it used to ?

Anything at idle ? she seems normal at idle .

I hope all this makes sense to someone or am I just overthinking it, could the previous owner have just changed the prop and that it ?

Thanks

One way is to make a short run and pull the plugs to check the condition/color.

It is possible to have jets with the correct number but the actual jet size NOT match the displayed number. Seen it many times, and it's a royal PIA to catch if you're not looking for it.

The real key here is getting the engine up to proper RPM's at wide open throttle. That is what most methods were doing (jetting or propping).

A higher pitch prop will result in LOWER RPM's, whereas a lower pitch prop will result in HIGHER RPM's.

wme carbs show .062 as standard size , when checking plug try not to idle cut it off fairly clean

ok , thanks for the feedback , i think ill pull one plug prior to look at just to have a baseline of what they looked like prior to running .

:thumb up2:

You didn't say what boat. if it's a lund 12p is probably right for a 16. There is no std prop for a 60hp.