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4.3 Mercruiser rough idle and hard start

 
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IamSteve



Joined: 31 Jul 2010
Posts: 2

PostPosted: Sat Jul 31, 2010 7:49 am    Post subject: 4.3 Mercruiser rough idle and hard start Reply with quote

Posting for a friend. He has an '06 4.3l Mercruiser with the TKS carb and he is having problems once the engine warms up.

It starts up fine when it is cold, but once it warms up to normal operating temp, it runs rough and seems to be really rich. You can smell gas if you let it idle for a bit. If you let it idle to long, it will die and then it is really difficult to get it started again. At cruising speed, it seems to be running fine, maybe a little rich but its hard to tell for sure.

This problem seems to have come on gradually. He noticed it has been idling rough the last few times out. Also says he smelled fuel lately off and on but didn't think it was coming from his boat (we usually tie up with several boats). Last weekend he didn't think he was going to get it started after stopping for a while.

He used to be a mechanic in a past life and rebuilt the carb on the advice of the local Merc shop. Same problem after wards, just $80 poorer...

Thanks for any advice you could offer!
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MikeW
Senior Member


Joined: 01 May 2006
Posts: 680

PostPosted: Tue Aug 03, 2010 4:11 pm    Post subject: Reply with quote

Sounds like there may be a problem with the choke. What is the engine serial number? Cool
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IamSteve



Joined: 31 Jul 2010
Posts: 2

PostPosted: Tue Aug 03, 2010 4:39 pm    Post subject: Reply with quote

I'll have to get it from him. He has bigger problems than just a rough idle. Last weekend he went out and everything seemed to be running great until he shut it down and then went to restart. He said it only turned over once and it was a real struggle. Checked the oil and it was full of water. I showed up after and towed him back. He checked the engine and 3 cylinders on one side all had water in them? Not sure what his next step is going to be...
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MikeW
Senior Member


Joined: 01 May 2006
Posts: 680

PostPosted: Wed Aug 04, 2010 7:12 am    Post subject: Reply with quote

Ok, you have a bad exhaust manifold. You need to replace both manifolds and risers. I suggest you pull all the spark plugs, crank the engine over to blow out any water and put some oil in each cylinder. The sooner you change the manifolds and run the engine the better off you will be. Cool
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