4.3 liter Merc I/O stalling after warming up.

M

MNboater24

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Jun 3, 2011
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I just bought a 16' Forester sport 166 with a 4.3 I/O. I took it out and after about 15 minutes it started to stall out. If I throttled down right away, I could keep it from killing completely...temporarily.
It would start right back up and go for between 10 sec and 10 minutes, then repeat. I plan to do a carb re-build, check plugs and take a look at the lower unit lube.
Anybody have a similar problem with one of these and have a place for me to start
besides routine maintenance stuff?
Thanks--
 
Don S

Don S

Honorary Moderator Emeritus
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Re: 4.3 liter Merc I/O stalling after warming up.

Check your automatic choke to verify it's not staying closed when warm.
 
M

MNboater24

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Jun 3, 2011
Messages
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Re: 4.3 liter Merc I/O stalling after warming up.

Thanks for the tip, if I do find that the automatic choke is staying closed, what is the remedy? I had her out again today after replacing all fuel filters and plugs (there was a rust hole at the bottom of the fuel/water separator filter) and it did the exact same thing, we let it cool down for 15 minutes, then it would take off like a banchee again...until it stalled shortly after, then repeat. Again, I appreciate the tip, this is my first boat.
 
C

copferman

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Apr 19, 2011
Messages
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Re: 4.3 liter Merc I/O stalling after warming up.

Had similar problem on my Forester. Two issues. One is choke. Depending on vintage, you may not be able to get replacement without someone trying to sell you complete carb. Check out the Carberator Doctor http://www.carbkitsource.com/HTML/about.html This guy is fabulous and saved me a couple hundred buck. The other issue is my fuel line got pinched under a bulkhead in a rebuild. When cold, the line was hard. As the motor heated up, the line soften and the boat stalled. Good luck.
 
D

dollarten

Petty Officer 2nd Class
Joined
Jul 28, 2011
Messages
136
Re: 4.3 liter Merc I/O stalling after warming up.

MNboater24 said:
I just bought a 16' Forester sport 166 with a 4.3 I/O. I took it out and after about 15 minutes it started to stall out. If I throttled down right away, I could keep it from killing completely...temporarily.
It would start right back up and go for between 10 sec and 10 minutes, then repeat. I plan to do a carb re-build, check plugs and take a look at the lower unit lube.
Anybody have a similar problem with one of these and have a place for me to start
besides routine maintenance stuff?
Thanks--
Click to expand...
One often oerlooked item is , the shift interupter switch . This little item is hooked in the shift linkage to allow you to pull the shift lever back in to nuetral . It's pupose is to snub the engine for a split second so you can shift to nuetral and will spring back before the engine dies . If the shift linkage is out of adjustmant the switch will stall the engine at the wrong time . Just a thought
 
M

MNboater24

Recruit
Joined
Jun 3, 2011
Messages
3
Re: 4.3 liter Merc I/O stalling after warming up.

Thanks for the feedback, I noticed that my brand new fuel/water seperator filter was full of sand. I started tracking the fuel line straight back to the tank and decided to take a look. I siphoned out a cup or two off the bottom and sure enough, there was a teaspoon of sand in the cup. Removed and cleaned the tank, replaced all filters and it runs good as new! Ya never know what youre getting with a used boat... Had one good weekend on the St Croix this summer! (A boulder took a chunk out of my prop.)
 
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