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Dumb questions about engine knocking noise

Posted: Fri Jun 18, 2010 1:00 am
by MTurvey
Ok I know nothing about engines (trying to learn as quick as possible), and ours is doing something funky. We've got the 318's - they say Kodiak?
Anyway - at low RPMs one of the engines knocks, and sometimes dies - but it seems to quiet down once I get up to 1000 rpms. Then today after I docked up & shut her down, that engine kept sputtering just like the car in Uncle Buck. I was seriously waiting for a backfire.... haha

Anyway - where do I start? :oops:

Posted: Fri Jun 18, 2010 6:37 am
by prowlersfish
Is the engine missing ? idling fast will cause it to run on after shut off .
also check the timing . if the timing is off or if its missing some one could have turned up the idle screw to compensate causiing the run on .

Posted: Fri Jun 18, 2010 11:46 am
by wowzer52
MTurvey, I agree with prowlerfish. It sounds like pre-ignition knock but a major tune-up (including the timing and dwell) will tell. Point gap will also change the timing..... By the way, my wife and I were just in Sitka a few weeks ago for a short stop over. We didn't have time to walk the docks or I would have noticed any Trojan boats. My wife thinks I'm obsessed. We went up on the Matanuska for a week of relaxation, a little break from work. This is the second time we've been up there. If we were going to move to Alaska, Sitka would be our choice, close to the ocean and good people..... Back to your topic, again, the timing would be a great place to start but I'm sure there will be lots of other suggestions.
Hello from your home town.

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Posted: Fri Jun 18, 2010 1:24 pm
by MTurvey
Ok - so its probably the timing. I told my husband to change the oil & change the fuel filters, but it sounds like a call to the mechanic is in order after this weekend.
We have guests in town so we kinda have to take them out fishing no matter what. Oh well - we only troll on one engine anyway :)

wowzer - looks like you got to see one of our rare rain free days! You were standing about three floats away from my boat in your pic - too bad you didn't get a chance to walk down the dock.

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Posted: Mon Jun 21, 2010 10:43 pm
by wowzer52
The next time my wife and I get up there I'll try to let you know ahead of time and maybe we can meet up for lunch and you can show us your boat.

Engine Knocking

Posted: Thu Jun 24, 2010 10:35 am
by Old Flame
Has anyone worked on the engine before the knocking occurred? I had a similar problem with my 318s in my old F30 after I changed plugs. Turned out I had switched spark plug wires 5 & 7. The engine ran, but had a bad "rod knock" at idle.
Cylinders 5 & 7 are next to each other in the firing order - 1-8-4-3-6-5-7-2 (or opposite order in the other engine but 5 & 7 are still in sequence.)