Cold start hesitation '08 SSV w/ 450.

I have been having an odd issue with our 08 SSV. On cold starts the boat idles very roughly and wont go over certain rpms until it warms up. This warm up period could be 5 minutes, 10 mins, 15 mins to the longest at 20 mins. No matter how far you put the throttle down, it stays at the same speed, and as it warms up it lurches faster. (So I try to cruise at low speeds until it works) Once warmed up (or whatever issues clears itself out) it works regularly.

We have been through several tanks of gas, so I dont believe there is water in the system, cleared all water filters and recently changed the fuel filter.

Any ideas or suggestions?


Thanks!



Mark

What engine is that? 8.1 Vortec 496 rated at 450 horse power? When were your spark plugs last replaced? Maybe the map sensor. It is simple to replace and runs about $65 bucks at the auto part store. That is where I would start and see if there is any improvement. If not then you may be looking at an injector problem. But that's where I would start. I am looking at getting a Scanner for my engine so that I can do more diagnosis.