to much fuel?

So I finally got my tune up all Done and I'm still have issues with the boost running. I have a 1990 4.3 mercruiser. Here's the deal

When you punch it, it stutters and slowly gets up to speed. Once its up to speed its fine.
When your sitting at idle, it slowly gets rougher and rougher. Sometimes it even will get so bad it dies.

So after playing around for awhile I took the flame arrester off and noticed if you open the butterfly on the carb by hand while its running Its fine.

So my question Is would that mean its pumping to much fuel into the carb? If so how would you turn it down? Or up?

Re: to much fuel?

Or could it be that your choke isn't adjusted properly? I'm not saying it is, just a thought.

Re: to much fuel?

jkeating said:

So I finally got my tune up all Done and I'm still have issues with the boost running. I have a 1990 4.3 mercruiser. Here's the deal

When you punch it, it stutters and slowly gets up to speed. Once its up to speed its fine.
When your sitting at idle, it slowly gets rougher and rougher. Sometimes it even will get so bad it dies.

So after playing around for awhile I took the flame arrester off and noticed if you open the butterfly on the carb by hand while its running Its fine.

So my question Is would that mean its pumping to much fuel into the carb? If so how would you turn it down? Or up?

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Sounds like a carb issue: You throttle up and it will get up but takes a while, but once up it runs OK. Check your accelerator pump. Have someone rev the engine up while your looking down the throught of the carb (wear safety glasses). You should see two small streams of fuel being oushed in the carb.

If your talking about the butterfly plate on top of the carb, that is your choke like CV16 mentioned and is not adjusted correctly. Adjust is to it is full open when engine reaches operating temp.

Re: to much fuel?

ok, it was a choke issue. the choke wasn't opening correctly so I opened her up. Now that it isn't dieing, it revs up and down differing 100 rpm or so. So the next problem... What could cause that?

Re: to much fuel?

What carb, Mercarb, Weber or Rochester? 2bbl or 4?

It does sound like the carb needs a good strip and clean out.

Re: to much fuel?

well, I just got sick of the damn thing and bought a new one.... the choke was bad and would not operate properly.... anyways moving on.... I recently had over heating problems... temp gauge would read 180-200 after idleing for about 10 mins.. Any ways, I replaced the t stat and water pump since water was leaking out the weep hole, also replaced the impellor about a month ago... is that normal? or is there something else I am missing in the system? or a bad temp sensor or gauge?

im not sure if this is something to do with the problem but I noticed when I first got the boat and ran it on the muffs water would run out around the outdrive all over even on the top side. Now it seems like it only comes out about half way up. not completely all the way to the top

and could this be because I cant put my outdrive all the way down? I can get it 3/4 of the way down before I hit the rocks in the yard

Re: to much fuel?

Any help would be appreciated

Re: to much fuel?

jkeating said:

Any help would be appreciated

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As you have 'fixed' the carb problem :facepalm:, and this is a new problem, start a new thread....

Re: to much fuel?

jkeating said:

well, I just got sick of the damn thing and bought a new one.... the choke was bad and would not operate properly.... anyways moving on.... I recently had over heating problems... temp gauge would read 180-200 after idleing for about 10 mins.. Any ways, I replaced the t stat and water pump since water was leaking out the weep hole, also replaced the impellor about a month ago... is that normal? or is there something else I am missing in the system? or a bad temp sensor or gauge?

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Impeller needs to be replaced every couple years. A bad impeller will cause over heating and once it over heats more issues can show up like not running right. When it over heats you need to make sure to get all the pieces of the damamged impeller out of the engine. They can loge themselves in oil coolers, T-stats and over places which can cause over heating.

im not sure if this is something to do with the problem but I noticed when I first got the boat and ran it on the muffs water would run out around the outdrive all over even on the top side. Now it seems like it only comes out about half way up. not completely all the way to the top

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Depends on what you mean by this. Some exhaust bellows are not attached directly to the drive, they only attach on the transom side. Depending on how high your drive is, and if this is the case it could be splatter. Don'y know need a engine and outdrive serial number.

and could this be because I cant put my outdrive all the way down? I can get it 3/4 of the way down before I hit the rocks in the yard

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If your drive is not down far enough you can be damaging your u-joints and drive bellows