pre ingnition?

[Link2052]

I have a 2003 4.3 merc not fuel inj. I get some sputtering when I shut the key off when I'm drifting. Is it because the engine is just ideling for to long and loading up? Because if I run to another spot and shut her down it's fine, would a plug change help? <br /> Any input would help, I'm a do it yourselfer any tips would help my engine has 100 hours on her<br /> thanks LINK

 

[Richard Petersen]

Re: pre ingnition?

I have found that a "after run" condition means the fuel/ carb and or the intake manifold is too hot. I think your engine is living in a space too small. Try this. Idle the engine to get it ready to after run. Leave it running. Lift the engine cover or hatch. Leave it up for 5 minutes. Turn it off. No after run due to more idleing cooling air. I am assuming the idle speed is correct and the mixture.

 

[a.d.mobile]

Re: pre ingnition?

what is the idle rpm? you will have to adjust it to 600 or a little less to stop this. you will also have to adjust the idle mixture. there is a special procedure for your engine, it should have a thunderbolt 5 which has to set to base time to adjust properly. the problem you have is run-on/dieseling, this can cause major issues if it sucks water in the clyinders. I did 1 last week I had to set it to 550 in gear to stop the run-on. bob

 

[Link2052]

Re: pre ingnition?

thank you for the info , my idle RPM is set to 600 , maybe I'm shutting her down to soon after a run back after a drift . I'm going out on Sat and I'll check out everything thank's again <br /> LINK

 

[Richard Petersen]

Re: pre ingnition?

Does the engine temp get higher during the long idle/ drifting times. Than after a cruise and stop? What is the difference if any.

 

[Richard Petersen]

Re: pre ingnition?

Did this start after any repair work? How long ago?

 

[Link2052]

Re: pre ingnition?

Well just to tell ya ,I went out today and got some sweet fat cows and the boat "Celtic Knot" was flawless <br /> Thank's to all I think the problem was shutting her down to fast,today I let her idle and then shut down no run on ! I also let her idle for a couple of long drifts and shut down .<br /> My idle is 550 rpm and the temp during drifts in engine compartment was 83 to 87 deg engine running I also turned on the blower to clear air I figured it couldn't hurt. <br /> thank you LINK