Cobaltchat.com

cmattj wrote: Wed May 23, 2018 11:48 am You'll need a scanner to see what the iac is being commanded for idle speed rpm . I would suggest having it scanned or throwing a Good Iac on it.

The money you'll spend having it scanned may saving you throwing parts at it.

thunder550 wrote: Wed May 23, 2018 10:21 am Welcome to the site!

What year is your boat? Can you hear/feel a difference in the idle speed, or are you just relying on the tach? Reason I ask...it's a fairly common issue for a tach on a boat to read high occasionally. Mine does it at the start of nearly every outing, I have to knock on the front of it twice with my knuckle and it goes back to where it's supposed to be. Let's rule that out as an issue first since it's a really simple solution.

Big Block Power wrote: Wed May 23, 2018 6:25 pm You can remove both battery cables and connect them together for 15 minutes then reconnect them and it will relearn the position. Let it idle for 10 minutes.

ctfortner wrote: Wed May 23, 2018 1:49 pm Hey, I guess a few more details would help huh. For some reason I thought I had posted my boat and pics before, but I see I have not. It is a 1995 220, with the 5.8. I bought it from a guy last month. He took to a service place and had them summerize and do an engine check, change oil, and even do a water test. It all checked out other than a busted oil pressure gauge and P/S was 3/4 quart low. I went an picked up there and before buying, we threw it in the water and I drove it around the lake for about 30 minutes. Hole shots, WOT, cruising, etc. Ran great, but we noticed it sounds like the idle was high and sure nuff, the gauge was reading aroun 1500.

The engine was replaced in 2011 with a (said to be) new Jasper engine. I know it is a Jasper in there because it is stamped by them with a serial number and I called and got the details on it.

Now, since I made that post this morning, and before I read yall's posts here, I have done the following. I disconnected the throttle cable, removed IAC valve and cleaned with TB cleaner, cleaned inside TB with spray and a brush. Put IAC back on, fired it up and she just purrs at 1500 rpm without missing a beat...so, no change.

Engine was hot by then so spraying solvent wasn't in my want to do list, will try on cold engine later today. I'm still thinking hard about that dam idle screw though. What now ? If it was a vac leak would the rpm bounce around? If it is a vac leak, would it be noticeable in running WOT on the water. I drove it before I bought it last month, performed flawless for 30 minutes, just idled high. No stutter, hesitation, stalling, nothing. It would be awesome to know what and how to adjust or check if the idle screw is in the factory position. Is there any manual that discusses that?

I don't think it is a tach issue, it definitely sounds a bit high, and on a cold start it is around 2000 RPM, and then will ease down to 1500 and settle in once warmed up. Has a slight "grind" to it going into gear, not real bad, just enough to feel it.

I would get a scanner, but where can you hook to a marine engine? I have done a little engine work here and there, mostly carbs, but this is my first marine engine experience. I have a laptop. I am in IT so I can handle that part if I knew what to get, unless its big $$$$