maverickmarine

hello can any one help, we have a 420se in stock that has a high idle speed problem the idle relay and the idle valve seem to be working ok we swapped them over with my 560sel and they seemed to work fine.there appears to be no vacume leaks it just idles at about 1800 rpm.any ideas?all responses welcome thanks

waybomb

Did you check the OVP? What happens when you pull the OVP out while the engine is running? Then put it back in.

Same with ISC - unplug it, what happens, plug it back in.

Same with ICV - disconnect wire connector, what happens, plug it back in.

Then spray copious amounts of gumout carb cleaner all over the air distribution hoses, and under the top half of the air intake, where the air distribution hoses cross underneath it. Does the idle change at all?

inthemedia

I traced my high idle problem to a faulty Throttle Position Switch (TPS). The TPS senses the position of the air butterfly valve. Unfortunately it's a bear to get to. Have to remove fuel distributor and air guide housing and all the stuffs that's in the way. In fact, I'm working on it right now. Because the air guide housing rubber has hardened over the last 20+ years, getting it off the metal butterfly housing throat is a real bear. In fact, that's where I'm stuck at the moment. I've loosened the hose clamp securing the air guide to the butterfly valve body and removed the 4 bolts holdling the assembly to the rubber mounting bushings but just can't seem to pull the assembly off. Anyone got a trick to getting it off?

Thanks,
T.C.

GRIMSTONE

Buy a hose removal tool from "Snap On" and slide it between the metal and the rubber---this tool will save you from breaking radiator necks in the future! GRIMSTONE.