Hard starting mpi mercruise 5.7

[bajadawg]

2005 Merc 5.7 MPI 350 Mag engine is hard to start!! only starts when throttle is 1/2 of full when COLD or at operating temp.Once started it runs fine and never stalls!!
Changed plugs & set gap, color of plugs is white/sand after 10 hrs run time, new dist cap & rotor, New IAC, New MAP sensor, new marine batterys 1000 amp hrs, Mercruiser tech spent 3 hours at $150 p. hour and still cant find the problemb!
Need help anyone have simular problemb?
Thanks

 

[wags23]

Re: Hard starting mpi mercruise 5.7

I'm having the same symptoms . I just replaced my iac and took boat out today and after bottom fishing for a couple hours had to give it throttle to start. No codes came up. Tested the iac by looking for a change in tach when unplugged no change. So changed the iac. tps maybe but the code should have come up .