2003 3.0 Alpha 1 rough start when cold

korygrandy

Senior Chief Petty Officer
Joined
Apr 14, 2010
Messages
698
I just bought a 2003 Glastron w/ the 3.0 mercruiser. Everytime I start the engine cold it's real rough. It usally takes 6-8 times before it wants to start and another 3-5 before it finally starts and then just chugs for a bit until I put it in gear. It idles around 450-550rpm and when it warms up it idles aroung 800rpm.

After purchasing the boat I adjusted idle from 1,000 to 800rpm because it was clunking a bit when I put it into gear. Changing the idle helped this a little but the boat is still starting real rough when cold.

Any suggestions?
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: 2003 3.0 Alpha 1 rough start when cold

Some how, I suspect you are a fairly young guy and never dealt with a carbed engine before.
The 3.0L engines will not idle cold, they need to be run at 1000 to 1200 for a few minutes till they warm up.
You may be way overdue for a tuneup, carb adjustment and who knows what other preventive maintenance.
The idle should be around 650 to 700 rpm in gear (not tied to the dock) when warmed up.

Have a look up in the Adults only/DIY stickies for manuals, and lots of other info.
 

korygrandy

Senior Chief Petty Officer
Joined
Apr 14, 2010
Messages
698
Re: 2003 3.0 Alpha 1 rough start when cold

Young...maybe...28 and this is my first boat. My dad had a carburated boat and I have dual carbs which I managed to sync up myself.

What all is involved in a tune-up? The boat was winterized prior to the season by the previous owner. All fluids are at proper levels.

I believe this has the TKS system because I see a module connected to the carb. I think this might be user error because the guy that sold it to me started er up first time just fine. I think I need to be patient and let it warm up before taking off.

After reading about this TKS it sounds like it should mix rich for easier starting though.

I'm willing to learn anything I can about this thing.
 

IES99

Petty Officer 1st Class
Joined
Jun 3, 2008
Messages
271
Re: 2003 3.0 Alpha 1 rough start when cold

I just bought a 2003 Glastron w/ the 3.0 mercruiser. Everytime I start the engine cold it's real rough. It usally takes 6-8 times before it wants to start and another 3-5 before it finally starts and then just chugs for a bit until I put it in gear. It idles around 450-550rpm and when it warms up it idles aroung 800rpm.

After purchasing the boat I adjusted idle from 1,000 to 800rpm because it was clunking a bit when I put it into gear. Changing the idle helped this a little but the boat is still starting real rough when cold.

Any suggestions?

Sounds like mine, although it usually starts the first time. Until these things warm up, these run rough. But then things are fine.
 

korygrandy

Senior Chief Petty Officer
Joined
Apr 14, 2010
Messages
698
Re: 2003 3.0 Alpha 1 rough start when cold

I must be doing something wrong because it started the first time I ever took the boat out. The second third and fourth time, no such luck. The second time I noticed there was a red RUN switch on the throttle and it wasn't pushed up. This was after I tried starting it like 8 times. I wonder if I screwed something up by trying to start it without being in the RUN position.
 

korygrandy

Senior Chief Petty Officer
Joined
Apr 14, 2010
Messages
698
Re: 2003 3.0 Alpha 1 rough start when cold

This was user error. I didn't know there was a big button on the throttle you can hold down to disengage the propeller and give the engine more rpm's.
 

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jasonachord

Seaman Apprentice
Joined
Aug 27, 2009
Messages
37
Re: 2003 3.0 Alpha 1 rough start when cold

I made this same mistake with my boat when I first bought it last year. My first boat and only boat I was previously experienced with was an outboard which had a warm up lever to help crank it when cold. No such thing on an inboard. I went and water tested the boat and it cranked right up and ran perfect. Next day I take the wife and kids out to the lake and I?m sitting at the ramp for like 30 min and the thing will not start. Luckily the guy I bought it from answered his phone and laughed as he walked me through how to engage the throttle only button and give the engine some gas and it fired right up. I felt like an idiot but we all have to learn from someone. :D
 
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