Decelereration stall and no start

[pepmyster]

I looked at the image and they do not look the same. The Merc is a plunger style.

[Viper]

Unfortunately the track record for parts when used in cars can't be used as a benchmark for longevity when the same part is used in a marine application, it's a totally different duty cycle and set of conditions. The IAC works more in a car than it does in a boat, and doesn't get laid up for half the year like it does in northern climates. Like any moving components, non-use kills them faster. Add to that the bad practice of spraying storage fluid into the throttle body for winter storage as an easy way of fogging the engine and it's no wonder they fail.

[Midnightsun]

Unfortunately the track record for parts when used in cars can't be used as a benchmark for longevity when the same part is used in a marine application, it's a totally different duty cycle and set of conditions.

I agree however in the case of the IAC I pointed to for the merc they fail horribly. I went through 4 in no time and these were the Merc originals at $150 a pop. Finally decided to go with the Ford equivalent ($40) which never failed me and to date the new owner has put on an additional 400hrs and still doing great. This may be an exception to the rule.

[Viper]

I also think manufacturing has taken some shortcuts. I went for years just replacing the odd one here and there but it seems that the last couple of years I've been replacing them quite often. It hasn't however been on units that I've replaced before so I'm talking original equipment. It just seems like last year and the year before were the years of the IAC for me. Probably replaced a dozen in two years which is a precedent at my end. Will the new ones last as long?...hard to tell but something tells me that like everything else, they don't build ANY brand like they used to.

[pepmyster]

I recieved my parts, IAC and plugs. At least the IAC has a warranty of 1 year. I'll give updates on the replacements soon. Thanks to all who have chimed in.

[pepmyster]

Sooooooo, The other owner said that the other owner replaced the plugs at 600 hours, WRONG! The plugs were the original AC Delco from the factory. They are now replaced with Denso Iradium plugs, IT16. Also, replaced the Starboard IAC , started the motors, they purrrrred. Did the sudden idle drop, beautiful. Now to start to learn how pilot this vessel!!! Thanks for all the input!

[Midnightsun]

Glad to see you got her all sorted out. Now get out there and enjoy her.

[km1125]

Did the plugs still have paint on them? That's the only way I'd say to determine if they were original. In my first boat I replaced plugs with the exact same type as the manufacturer had installed "just in case it made a difference".

[pepmyster]

Yes, painted right from the factory. 750 hours on them.

[bud37]

Source of the post Sooooooo, The other owner said that the other owner replaced the plugs at 600 hours, WRONG! The plugs were the original AC Delco from the factory. They are now replaced with Denso Iradium plugs, IT16. Also, replaced the Starboard IAC , started the motors, they purrrrred. Did the sudden idle drop, beautiful. Now to start to learn how pilot this vessel!!! Thanks for all the input!

Thanks for posting the resolution.....good its working right........