Knocking noise

[Bitzco]

My two cents on the knock issue. I have had three Toyotas now and have never heard the slightest knock. I can't always get Chevron and have used gas at Lake Powell and Lake Mead that was "premium" and just didn't smell quite right. They are notorious for bad gas at those lakes but there are no gas stations around. Even with the crap gas, I've never heard a knock. Plugs, Plugs, Plugs.

[HCollado]

 

Wow, changing spark plugs yearly dosen't sound right. I have yet to change mine, '99 boat with about 175 hours. Now that I've read this, I'll go ahead and order a set of the Denso.

[2000epic]

I bought my boat (a 2000 model) brand new just under a year ago with 2 hours on it.  At thirty hours I fouled a couple of O.E. plugs.  This leads me to believe that non-use or intermitent use is harder on these plugs than total hours.  I've been told these plugs last 10 years, and conversly I've been told they should be replaced yearly.  As a happy medium I now keep an extra set in the boat.

[shawn]

changed all the plugs today and took her out, what a change, i gained four mph. You guys were right, no more knocking.

[toyotafreak]

Man, all this talk about plugs makes me want to try a set.

HCollado, you ought to change that avatar pic before Pete has too. Thanks. Got the board of directors from TOYOTA lurking here, wouldn't want to give them wood.

[dawsonr]

I agree, non use is more of a problem with the plugs than hours of use.  I had a problem of missing after just a couple of days of sitting idle.  This forum kept saying to change the plugs, but at 96 hours and they looked OK, I just had a hard time justifying that avenue.  I finally broke down, spent the $18 per plug and changed them.  What a difference.  I may well start changeing them each spring.  It's worth it not to have some MC ownerlaugh at my miss-firing Epic.  Especially when I brag about the fuel economy of the Epic. 

[lesman01]

I took my boat out for the first time this season after sitting up all winter. I used the "water ready" winterization where they run some form of antifreeze thru the system. The boat fired right up, which always amazes me. Anywho, after running it WOT for several minutes, then doing some boarding and cruising, at the end of the day while cruising, the motor sorta started surging for about 5 minutes. I attribute this to bad gas, or some combination therof. After that it did not hit a glitch in about an hour of running time.

Could that be plugs? Or is it likely just a spot of bad gas.

One more odd thing that happened was that while geting up to plane once the motor just went dead. Now, my 17 month old son could have very well turned the key off. He loves to play with it...Anyway, when I put the boat back in neutral and turned the key over to crank her back up, it would not fire. It wold turn over, but not fire. Then i noticed that the computer was not on like it normally is when the ignition is turned on.  Humm... Anyway, i let it sit for 1 minute, then turned the ignition on and heard the familiar weezing of the dashboard and saw the Toyota Marine Sports logo on the computer.. then she fired right up. It only happed once, but once too much for my sanity.

The only thought i had was that the computer needed to reboot after being abruptly shut down. Anyone ever had anything similar? Is it time for  new mdc thingy?

[cyclone]

Your kid turned the switch or pulled the plug or pushed the STOP button if you have keyless. Or something. Nothing to worry about. I blame all things that happen to my boat on children. There are very powerful natural forces working against us, we are nearly powerless. They are SUN, WATER and CHILDREN:) Cheetos are up there too. They are usually in the hands (or were recently) of CHILDREN.

Your MDDC doesn't have anything to do with ignition, the problem came from the power going to the engine computer from the dash keyswitch or the silly deadman switch. Remember that having the deadman switch bypassed with a wire tie runs up your hour meter:(

[wakejunky]

lesman I believe what you are experiencing is the factory toyota ECM relearing new values. It does this anytime the battery has been disconnected or the EFI fuse has been removed. My boat has done this every time I disconnect the battery. First time out this year it took almost 10 minutes to get it to idle properly. It usually takes one or two trips out before I stop experiencing "glitches". If you just run the boat at WOT the ECM will only learn that range of the powerband. The hardest thing for any engine to do is idle. the constant adjustment because of the low rpm make that ECM and idle speed motor work overtime. I see this happen all the time at the dealership when working with ECM issues. I have noticed our boats really take along time to learn. Try driving the boat at all rpm and load ranges possible and it will iron out all the kinks. the symptoms can look very much like bad gas or bad plugs, but give this a shot first. Toyota and Lexus ECM are extremely slow compared to GM and Ford, or any other vehicle. This is what also keeps our engines so reliable. They actually miss some of the glitches that other ECM's catch. Its like comparing processing speeds with home computers. GM is the latest greatest Pentium 4, and Toyota is like an old 386. Sad but true. Just thought id throw in my 2 cents.

[cyclone]

That makes perfect sense, I've observed exactly those kind of behaviors with cars, but I must say that I disconnect the battery after every time out, and I never have idle problems since I replaced my NGK's with densos about two years ago, at 400 hours. . It runs like a top all the time. I just put mine back in the water after the winter, and I replaced my starting battery this year, and it started right up and idled perfectly at 700 rpm the first time out. I just haven't seen those symptoms with my Epic.

[lesman01]

Thanks. I'll just see if it happens again next time out. It did idle perrrfectly from the get go...though. And it seemed to run really lean the first hour or so.