Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

[donie]

Hi all<br /><br />Brough my merc 3.0 out the other day and it was misbehving badly. Hard enough to start but when it got going it idled ok. Had problems taking off and it was hesitant with poor power on take off. Once it would get going it was OK.<br /><br />When left running idle it would cut out after a minute or two. <br /><br />It was going fine before this and I tuned it up a few weeks ago myself. I'm not an expert but I was happy with the result. I was suprised it started to behave like this. <br /><br />Fan belt may be loose as I noticed it was screeching at startup. Not sure if this could lead to these problems?<br /><br />Thanks for any quick help<br />Donie

 

[magster65]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

I guess it's not stale gas by the sounds of it. I'd start by;<br />Pull your dist. cap, make sure it's dry under there, spray a little wd40 in it and wipe it out...<br />Check all your leads for grounding problems or being loose...<br />Remove the spark arrester and look in the carb to see if you're leaking fuel...

 

[donie]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

OK - I'll try that. I'll let you know how I get on with it. Any other tips would be great as I have a few hours to sort it out in the morning.<br /><br />Thanks for the help. I really appreciate it as I'd hate to have to drop the money on this boat becasue it would appear to the buyer to be dodgy. I know this is only a small problem but he might think otherwise. There is only about 50-60 hours on the motor.<br /><br />Thanks<br />Donie

 

[P.V.]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

Your local champion spark plug guy can sell you the latest plugs for that motor. Give him the serial # and install them. I bet it will run just fine !!!

 

[donie]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

Hi all<br /><br />Cleaned up everythin but the motor is still the same. Didn't try the spark plugs yet. Have the plugs been changed on this engine?<br /><br />It's a 2000 model 3.0 ltr engine. What plugs should it have? I presume when you say to get the lates one it meand the specs have been changed.<br /><br />Thanks for the feedback.<br />Donie<br /><br />ps: I'll get the serial number and post it here and maybe somebody will give me the specs for the correct plugs.

 

[donie]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

Hi all<br /><br />Engine serial number is 630385. If that is helpfult to getting the right plugs then please let me know.<br /><br />The manual recommends Champion RS12YC or NGK BPR6EFS plugs. I tried to get these but failed and the guy gave me an equilavent called DENSO T20EPR-U. I know sweet * all about plus so it this plug that I have fitted the problem. Has Mercruiser recommended a different set of plug to the ones I mention at the top.<br /><br />BTW: The guy I was selling it to was happy enough with the engine and didn't even notice the problem. He'll get back to me next week. Hopefully, I (we) can sort out this little problem before he takes it away.<br /><br />PS: If do need plugs is there anywhere on the web I can buy this. It's so hard get anything over here.<br /><br />Thanks for the help. I really appreciate it. <br />Donie

 

[donie]

Re: Mercruiser 3.0 rough running. Buyer coming tomorrow!!!

Is there a possibility that this is a spark lead problem. Could it be the timing? It was running perfectly two weeks ago and this just started all of a sudden. I've checked most obvious thing like loose cables etc.<br /><br />Donie