'06 Bravo III 8.1 running but weird ...

Original owner of this Cobalt 226. Since day 1 thru today motor has started immediately and dies once; always starts & remains running upon re-start. I do "help" it with a little throttle. Not sure I should need to do that on a FI engine, but I have since day 1.

I allow the engine 3 - 4 minutes to warm up before motoring along - not sure if this is long enough?

First time trying to plane, some studdering and rough running, but it slowly does plane. This is with somewhat less than WOT; trying to be nice to it as it wakes up.

Once planing, we can motor along fine, but the engine is slightly rough and at say 1/2 throttle or so surges ahead (not surges as in power outages), like I'm punching it momentarily, which of course I'm not; not even touching the throttle.

As the day goes on and the motor has more run-time on it, 1/2 hour, 1 hour, etc, it gets smoother and smoother to where it seems just about perfect for the rest of the day. Very, very slow to wake up would be a good description ... but I've never had an engine take an hour to wake up.

Any ideas?? Live with it? Nothing too bad wrong? Thank you ...

Sounds like it it time to have the fuel module serviced. Paint in the regulator is likely causing too much fuel pressure and poor operation. As for the stalling the IAC muffler is probably plugged up and a possibility that the IAC is no longer functioning correctly.

extrapolator said:

I do "help" it with a little throttle. Not sure I should need to do that on a FI engine, but I have since day 1. I allow the engine 3 - 4 minutes to warm up before motoring along - Any ideas?? Live with it? Nothing too bad wrong? Thank you ...

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No need to live with it when you or a Mercruiser service shop should be able to make it right one way or another.

As an original cobalt owner I am truly surprised that it went on for this long and that it seems you've never mentioned to either cobalt via surveys they send out or to a service shop for maintenance that hopefully you have done since ownership?

From what I know about cobalt, if you would have let them know how it was running, they usually would make some sort of effort to get you to bring it in for a check up. Or do you do your own service work and plan on taking this issue on now yourself?

You shouldn't have to open the throttle at all upon startup and as an IAC test, the next time out while in neutral gear, just turn the key to start and see if it will start on it's own like it should + stay running.

In some cases before starting the engine, you sometimes may need to prime the fuel system by turning the key on for a few seconds while the fuel pump primes, then key off and back on for second prime then crank to start. Doing that may help with the initial engine stalling when cold.

3 - 4 minutes would be long enough to get it warm enough for mild take off. If possible though, it's best to idle it up around 1000ish RPM for a number of reasons, though it's not absolutely needed it's just much better for the working system is all.

Is your engine serial number handy?

One item on the list to start off with would be finding out what the fuel pressure reads.

Also you would need to get an Marine scan tool from Rinda technologies if you're going to do it yourself.
http://www.rinda.com/marine/mtspec.htm

boat_tech said:

No need to live with it when you or a Mercruiser service shop should be able to make it right one way or another.

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That's good news!

boat_tech said:

As an original cobalt owner I am truly surprised that it went on for this long and that it seems you've never mentioned to either cobalt via surveys they send out or to a service shop for maintenance that hopefully you have done since ownership?

From what I know about cobalt, if you would have let them know how it was running, they usually would make some sort of effort to get you to bring it in for a check up.

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I guess I'm not much of a complainer. I've never received a single Cobalt survey, that I know of. I bought it from what was then a Cobalt dealer in Orlando, Central FL Boating Center. However, I live over an hour north of Orlando, and I believe they went out of business some years ago.

boat_tech said:

Or do you do your own service work and plan on taking this issue on now yourself?

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I've done some of minor maintenance myself, including keeping fluids topped off, but have also taken it to Miller's Boats in Ocala almost every year. Even that is about a 45-minute drive, so I like to keep it to a minimum. I probably need to get over that.

boat_tech said:

You shouldn't have to open the throttle at all upon startup ...

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Glad to hear that; would be nice to simply turn the key to start ... and stay started ... like some of my friends' boats.

boat_tech said:

... and as an IAC test, the next time out while in neutral gear, just turn the key to start and see if it will start on it's own like it should + stay running.

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After it's fully warm (1/2 hr to 1 hr ride or more) it does then start without any additional throttle assistance.

boat_tech said:

In some cases before starting the engine, you sometimes may need to prime the fuel system by turning the key on for a few seconds while the fuel pump primes, then key off and back on for second prime then crank to start. Doing that may help with the initial engine stalling when cold.

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I have never heard of that procedure, even though I feel as though I'm thoroughly familiar with the owner's manual. Maybe I missed that.

boat_tech said:

3 - 4 minutes would be long enough to get it warm enough for mild take off. If possible though, it's best to idle it up around 1000ish RPM for a number of reasons, though it's not absolutely needed it's just much better for the working system is all.

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I can certainly make that a habit. I also didn't know that should be standard MO. We're boating tomorrow, so I'll give that a try & post whether it improves things.

boat_tech said:

Is your engine serial number handy?

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The boat lives right out in my garage, so I'll post it shortly.

boat_tech said:

One item on the list to start off with would be finding out what the fuel pressure reads.

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I'll have to look up to find out how to do that. I don't know how right now.

boat_tech said:

Also you would need to get an Marine scan tool from Rinda technologies if you're going to do it yourself.
http://www.rinda.com/marine/mtspec.htm

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Let me check into that.

Thanks so much for y'alls' feedback guys ... I sure do appreciate it.

Docksidemarineservices said:

Sounds like it it time to have the fuel module serviced. Paint in the regulator is likely causing too much fuel pressure and poor operation.

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Paint?? Yikes ...

Docksidemarineservices said:

As for the stalling the IAC muffler is probably plugged up and a possibility that the IAC is no longer functioning correctly.

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Wow, I've never even heard of an IAC muffler ... going thru boat ownership life a little clueless I guess. Going to look that up right now ...