Newbie - engine running on

nzmarty

Recruit
Joined
Apr 21, 2005
Messages
2
hi there. newbie to this forum - not to boating though. i have a 04 bayliner 175 with 3.0 mercruiser. since i bought it though, it runs on, if shut down soon after coming into the beach - we use it mostly for boarding & skiing. if i let it idle for a minute it is ok. it also huffs a little under hard accelleration, but i see that is somewhat normal from low rpm with the 3.0.<br /><br />my Q is, what is the recommended plug? i think i'll have to go cooler, as the ones i am running must be getting too hot. i've tried riching it up, and the timing is bang on according to the dealer. neither fixed the problem.<br /><br />cheers all
 

Trent

Captain
Joined
Nov 17, 2001
Messages
3,333
Re: Newbie - engine running on

This is a common problem and Mercrusier issued a service bullitin on it. It basically said to check the timing, run a higher grade of fuel and run your blower more and also let the engine idle two to three min. before shutdown. This is all to do with the high temps in the engine compartment.
 

trog100

Senior Chief Petty Officer
Joined
Dec 1, 2004
Messages
751
Re: Newbie - engine running on

if all have to do is let it idle for a minute before switching off running on isnt really a problem.. course pre-ignition (huffs a bit) your terminolgy aint that exact.. he he) during acceleration could be.. gas with a higher octane rating is worth a try if u can buy it..<br /><br />trog100
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Newbie - engine running on

Let me tell a fairy tale of a 2004, 3.0L Mercruiser engine.<br />Once upon a time a Marine Mechanic had a customer with a 3.0L Mercruiser engine, the engine was very hard to start, hard to keep running till it warmed up and dieseled severely when shut off, even after idling for several minutes.<br />The timing was spot on, and since this engine had the EST distributor was set at the proper timing per the manual and done while in the base timing mode. Still the same problems. It was obvious the engine was running too lean but with the anti tamper devise on the carb mixture screw, it was impossible to adjust it richer.<br />Knowing the lean mixture was probably the cause of many past 3.0L engine failures, the MM (Marine Mechanic) decided, against his better judgment, that the problem with the engine would be a constant problem if not prevented somehow.<br />Knowing full well that the all powerful California EPA may rain fire and damnation on him for the rest of natural born life and on into the unknown after death, the MM decided to take the matters into his own hands and remove the tamper proof cover over the idle mixture screw. He soon found this to be a very difficult task, but somehow managed to remove it without destroying the carb or the screw. (He later found it would have been much easier to order a new mixture screw and just replace it and go ahead and break the old one off.) <br />Finally after the success of removing the dreaded seal, he backed the mixture screw out approximately a quarter to a half turn. the engine then smoothed out and ran great, idled smooth and slower without dieing and was even easy to start for the first time in it's life, even cold, and never dieseled again when shut off. <br />While the MM is worried about the hereafter and the consequences of his irresponsible act against the all powerful California EPA and all the other mini EPA's of the world, along with the consequences of his complete disregard for the Mercruiser procedures outlined in his service manual, the dastardly dead was done...............<br />The customer, however, wondered why his boat was now working perfectly but the poor ole MM was unable to tell him the truth, and worries to this day he will be found out and that upon passing he will be sent to the worst part of purgatory for his serious misdoings, but I will......uh, sorry about that, he will be happy in knowing that the boats engine will now live and last for many trips to the great fishing grounds of the owner.<br />Please understand that this is only a fairy tale and should only be told in the proper company. DO NOT try this at home as you could also be condemned to eternal damnation of the EPA gods.
 

waterone1@aol.com

Lieutenant Junior Grade
Joined
Oct 10, 2004
Messages
1,235
Re: Newbie - engine running on

L.O.L....Is there a moral to this story?? did the marine tech live happily ever after...in (just guessing here) ALASKA??
 

cny boater

Cadet
Joined
Feb 19, 2005
Messages
9
Re: Newbie - engine running on

Don, do you have any experience with Merc's 3.0L anti-dieseling kit 862656A1?
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Newbie - engine running on

Yea, it's a $275 way to make a lean running/hard starting/dieseling 3.0L stop dieseling.<br />But it doesn't cure all the other problems caused by lean running.
 

trog100

Senior Chief Petty Officer
Joined
Dec 1, 2004
Messages
751
Re: Newbie - engine running on

my curious mind would be interesting in knowing just how this $275 kit went about trying to achieve its intended purpose.. and just what is in it..??<br /><br />my view as to why those engines have a tendancy to diesel based on what i learned back in the days when cast iron heads were common on cars is that the over 9 to 1 compression ratio is on the high side.. i think they are best used with 98 (ron) octane rating gas.. they were never designed to run on the unleaded lower octane rating stuff we use today..<br /><br />showing my age here but i went thru the phase before unleaded became the norm.. everyones engine starting pinking and knocking a little and some starting dieseling..<br /><br />what happened in the UK was this.. gas came at the pumps with octane rating numbers.. 100 being the best.. sports cars and such needed it.. <br /><br />98 came next.. still good stuff and most "normal" cars were happy on it..<br /><br />then came 95.. and even 93 i think.. <br /><br />then the powers that be decided that octane numbers were too complicated for joe public and they same up with what they called a "star rating"..<br /><br />5 stars.. the best 100 octane stuff..<br /><br />4 stars.. the good 98 octane stuff..<br /><br />then we had 3 stars and 2 stars down the bottom end..<br /><br />then they decided that lead in petrol was bad news .. lead was connected to the octane rating.. the 100 octane stuff had more lead in it than the 92 octane stuff.. <br /><br />so things started changing.. quitely behind the scenes they never told any one they were doing this.. they started to reduce the lead contend of petrol..<br /><br />5 star 100 became 98.. <br /><br />4 star 98 became 96..<br /><br />3 star 96 became 94..<br /><br />this all happened slowly over a two year period and the star rating at the pumps remained the same.. bit sneaky when i think back buts its exactly what happened..<br /><br />many a mechanics head was scatched trying to cure the wierd increase in engine pinking and associated problems.. the fairy story mechanic back then most often settled for retarding the ignition just enough to cure the problem..<br /><br />trog100 <br /><br /> <br /><br /><br />trog100
 

nzmarty

Recruit
Joined
Apr 21, 2005
Messages
2
Re: Newbie - engine running on

as i said, the timming (sic) is bang on, as per the MM. fuel is 96 RON unleaded. i can get 100 locally, it's just a bit dearer. i think i'll richen it up, run a colder plug, and fit a 1 minute turbo timer to it. on the up side, there's no cal EPA over here! hell, i even ride an Aprilia RS250.....
 

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: Newbie - engine running on

That ain't a fairytale, that's a nightmare!! :eek: <br /><br />Go ahead and adjust the idle mixture, it ain't a problem in NZ & Aus...........................<br /><br />and welcome to i-boats!!<br /><br />Aldo
 
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