Opti-Max idle

[basscatlildave]

I have a 99 OptiMax with 75 hours on a reman Merc powerhead. I took it out in Nov and ran fine until I started to head in and it wouldn't idle. It would try to idle about 400 - 200 rpms the die. I could keep it running with my hotfoot at 700 rpms. The fuel was pretty old so I came home and drained the tank and replaced the hoses new bulb and filter. It has always had 100% gas with seafoam and stabil in every tank. Today the idle surged between 300 and 700 rpms then died. Once past idle it ran fine all the way up to the limiter and no problems a a steady 4000 rpms. I brought it home and it smelled very rich on the hose and I can't keep at an idle. Where do I look next?

[johnboy 88 vegas]

Get it scanned with a DDT box.....could be just spark plugs or tps if your lucky after running that old gas.

[3springers26]

a scan tool will tell you opens & shorts ,& data,, you Still need to check mechanical... Fuel in the air side of the fuel rail will cause a rich condition @ idle it can't run on it but @ higher rpm's it can ... it can be a tracker valve, fuel or air regulator diaphrams, stuck open direct inj.. this type of failure will efect all cyls..

[half fast]

Another test would be to pull the injector or coil harnesses off one at a time to see if one cyl is dead or not.Have seen plenty of failed coils on those. hf...

[techteam]

check for leaks in air injection.

[flabum1017]

start with the basics.... fuel and air pressure check,,,,,, as mentioned above, High fuel pressure will float the injectors making it run rich. Fuel should be 10#'s higher than air......80/90 anything higher will make it run rich. Check for raw fuel in the bottom air cross-over hose (broken Diaphragm), check the lift pump diaphragm, will pump raw fuel into the motor through the pulse line if broken diaphragm..... Check the vent hose coming out of the top of the fuel resevoir for fuel while running, a stuck float needle and seat can make it over fill and dump into the engine..... etc.....

[Revolution141]

If you get a small pin hole in air line from compressor to fuel rail it can just muck it up enough not to idle but may still run once you crack the throttle. Had it happen on several occasions! Check that hose.