merc. 4.3 won,t stop running

[Scott28641]

I have a 2002 183 chapparel with 60 hrs., with motor warm i turn the key off and i get run-on i run high grade gas 93 oct my temps run at around 160 i have adjusted the timing some both ways with no change in the run-on. it is a carburated motor. the run-on continues for about 10-30 seconds after i have turned the key off

 

[Trent]

Re: merc. 4.3 won,t stop running

Their is a service bullitin for this problem I dont have the number in front of me but it says... Run the blower more and before shutdown let the engine run a few min. It lets the engine cool down. Try it. If it keeps it up carry it to your dealer. Run on can lead to water being sucked up the exhaust and destroying the engine.

 

[elpaso]

Re: merc. 4.3 won,t stop running

A high idle, rpm can cause problem.<br />Where is timing.<br />160* ? Hot engine does same.<br />Do you let engine idle for 2-3 minutes<br />before shutdown ?

 

[Scott28641]

Re: merc. 4.3 won,t stop running

I have tried all of that. who could i get in contact with about the service bullitin. I have let it idle for 5 min and it still does it

 

[Bondo]

Re: merc. 4.3 won,t stop running

Somebody here Must have a link to the Merc. Service Bulletins......

 

[DHPMARINE]

Re: merc. 4.3 won,t stop running

Scott 30 seonds of run on is a long time to be putting this strain on your engine.Stop it until you get it fixed.<br />There are several ideas in the bulletin.Why aren't you going back to the dealer where you bought this boat?<br />DHP

 

[Dunaruna]

Re: merc. 4.3 won,t stop running

MCSB97-17

 

[achris]

Re: merc. 4.3 won,t stop running

Scott,<br /><br />Welcome to the club! The club of owners with these problem carbs. It's a 4bbl Weber, right? and don't tell me, after you have be sitting for about 10 minutes it's a problem to re-start, takes about 30 seconds of cranking and sometimes you can smell gas, like it's been flooded. Also if it's been sitting for a couple of days or more, it takes an age to get fuel back up to the carb.<br /><br />I have lived with this problem for 10 years on my 4.3 and NOBODY can help. The problem is the carb dribbles after shutdown. The carb manufacturer says it can't do that. Bull****! I have taken the carb off the engine and watched it dribble! Mercrusier are about as helpful as a bucket under a bull (or words to that effect). And none of the other service companies have hear of it. Again, bull****. You are the second person in 2 months on this site and I have 2 friends with the same carb, with the same problem.<br /><br />I wish I could offer a solution, but sorry I can't.<br /><br />Chris.............

 

[Wellcraft 89]

Re: merc. 4.3 won,t stop running

Are these engines running hot ? is fuel boiling ? <br />are their spacers under the carbs?<br /><br />The float in the carb is set too high or they are saturated and not shutting off the fuel to the bowls. which cause dribbling of fuel into throttle bores<br />It can also be a defective needle and seat attached to the float.<br />Of course their can be other problems like lots of carbon build up in combustion chambers <br />ingnition timing Wrong sparkplugs.(heat range)<br /><br />Rich

 

[DHPMARINE]

Re: merc. 4.3 won,t stop running

Scott follow dunaruna's info.start at the top,work your way down.<br />gas brand could be it,but does the owners manual ask for 93 octane?Also what is the idle RPM?<br />Run your engine,warm it up.what is the rpm reading?Rev it up,then back to idle.what rpm?Put in forward rev it up,and back to idle.Same thing in reverse.if the rpm is not the same,adjust your throtle cable 'tighter'to the idle screw.<br />DHP

 

[Bondo]

Re: merc. 4.3 won,t stop running

And cut the Timing back a Degree or two.....

 

[bluewater19]

Re: merc. 4.3 won,t stop running

I have a 2003 4.3 with that had the same problem. I saw the trouble bulletin posted here last year. My engine compartment is very tight. Here is what I did to fix my run on. I lowered my idle to 600rpm in gear, switched to 91 octane gas, went one range colder with the spark plugs and had the dealer set my timing back 2 degrees.even now if I try to run 89octane it will run on a little bit. I always run the blower when pulling a tube or skier and let it idle for a little bit before turning it off. These are 2bbl carbs by the way. This is a very common problem with the vortec motors when GM switched to the vortec heads it raised compression (9.5/1)to the point that this motor really wasn't made to be run without fuel injection and a computer. Mercury and volvo continue to put carbs on them because they are cheap.

 

[achris]

Re: merc. 4.3 won,t stop running

All the suggestion above will help to cover up the problem. The actual problem is the dribbling carb. <br /><br />Bluewater19, <br /><br />Do you have to crank the engine for about 30 seconds after you have had it shutdown for more than about 5 minutes? And is the carb dry after a few days at home?<br /><br />Chris...........