Off Idle problem for 96 Mrec. 225 EFI

[RobinR]

I have a 1996 Mercury 225 EFI outboard with a interesting problem. The engine will idle at @650 with no problem. When placed in gear the RPM drops to 400-450, engines chugs, and dies. After restarting engine is totally loaded up and requires high rev to clear before proper operation. This condition has been going on since it was new. I have taken it to several dealers, with poor results,(I had to fix their fixes). I have checked/replaced/or adjusted the fuel sys. TPS, spark, plugs (yearly), Idle speed, mech. oil pump lever, thermostats. Has anyone heard of this or have any ideas?<br /><br />Thanks in advance

 

[sirlespat]

Re: Off Idle problem for 96 Mrec. 225 EFI

check the trottle valve opens at least a little when you go from idle to ingear. It can be that simple and get missed. I think that the engine need a little bit of throttle to overcome the load of the gears.<br />best regards

 

[RobinR]

Re: Off Idle problem for 96 Mrec. 225 EFI

Thanks for the input sirlespat, I've messed around with the Idle speed controler with poor results. If I ajust this screw so that off idle is between 600-700 RPM, idle speed becomes 1200 and seems to surge hi and low. Any other thoughts would be welcomed.<br /><br />Thanks <br />Robert

 

[ODDD1]

Re: Off Idle problem for 96 Mrec. 225 EFI

hi robin i dont know if i can help but it sounds like a setup problem. if the tpi is set to spec [maybe on the lean side] and this prob occurs you might be dealing with a sensor failure. a coolant temp sensor tha t goes open curcuit will cause these motors to go way rich. have you you had a powerhead replaced on this motor? you might have bleed hoses incorrectly routed on motor. [there are a lot of em] if you are checking them make rure the check valves on the crankcase cover work [can suck out the hose but not blow in] lastly did anybody do a leakdown test on the injectors? a drooling injector will do the same thing.......good luck.

 

[RobinR]

Re: Off Idle problem for 96 Mrec. 225 EFI

Hi ODDD1,<br />Sorry it took so long to get back with you. You rise some interresting points, I also thought it might be a setup problem but every thing seems to check out. If the coolant sensor went wouldn't the alarm go off? Also, if the coolant sensor were bad and the engine went to open loop wouldn't the fuel go lean? Finily, I put oneway check valves in the bleed lines upstream (cylinder side) and pointing at the manifold, do you think this could cause this problem (rich condition)?<br /><br />Thanks<br />RobinR

 

[ODDD1]

Re: Off Idle problem for 96 Mrec. 225 EFI

If the coolant sensor on head goes open circuit it wont fire the alarm...all coolant sensor doer is modify the information the throttle position sensor sends to the computer. if either one goes into fault the motor goes to a fixed rich setting. but this aint imporant...the arrows on those little brass check valves better point AWAY from theintake/reed blocks or yer bleed system wont work....and it will idle POORLY. Better take another look at them.