3.0L pinging/detonation sound

[Jmunk]

I'm helping a friend with a 99 Searay 180 with a 3.0L Mercrusier. Here is some background on the situation: He bought the boat knowing it had not been used in two years, and had not been winterized since last used. The block had a few cracks on the left side and he has used JB Weld in the past to fix other 3.0L. Pulled the manifold to get good access to the block to repair cracks, cracks repaired by drilling out ends, inserting set screws, ground cracks out and filled with JB Weld. Carb was cleaned, new rotor, new dist cap, new spark plugs, new impeller. Old gas drained out and only a few cups were left and filled with half tank of 87 octane fuel.

Runs great on muffs, took out for lake test today. Ran good at idle, checked for oil and water mixing and no signs. Once we got a load on it and went to get on plane heard a rattle coming from engine that sounds like detonation. It was fine below 2000 or so RPM. Sometimes getting up on plane it would not make the noise, but after a minute of being on plane it would rattle, we backed off throttle some and it would stop. In idle when reved up it does not make the noise.

My first thoughts are that the noise is detonation and that the timing needs checked, or the fuel he couldn't get out of the tank was bad and mixed with the fresh 10 gallons and wasn't always burning good. Check timing and put in 93 octane fuel.

I have a fear the head is possibly cracked or the manifold is cracked and that is also causing the noise, but I would imagine that it would ping/rattle/detonate every time it had a load placed. Not sure if it was me hoping it was better or if it did get better after we put a can of seafoam in the fuel.

Suggestions?

 

[alldodge]

Re: 3.0L pinging/detonation sound

Sorry but prior to using the JB weld I would use it as a flower pot. You could have a great ride for a while but sooner or later your going to need help being pulled out of the water or hauled in. Honestly I wish you well and nothing happens.

 

[Jmunk]

Re: 3.0L pinging/detonation sound

I've seen the JB Weld fix the cracks in the blocks and they last years. Thanks for the help?

 

[Bondo]

Re: 3.0L pinging/detonation sound

I'm helping a friend with a 99 Searay 180 with a 3.0L Mercrusier. Here is some background on the situation: He bought the boat knowing it had not been used in two years, and had not been winterized since last used. The block had a few cracks on the left side and he has used JB Weld in the past to fix other 3.0L. Pulled the manifold to get good access to the block to repair cracks, cracks repaired by drilling out ends, inserting set screws, ground cracks out and filled with JB Weld. Carb was cleaned, new rotor, new dist cap, new spark plugs, new impeller. Old gas drained out and only a few cups were left and filled with half tank of 87 octane fuel.

Runs great on muffs, took out for lake test today. Ran good at idle, checked for oil and water mixing and no signs. Once we got a load on it and went to get on plane heard a rattle coming from engine that sounds like detonation. It was fine below 2000 or so RPM. Sometimes getting up on plane it would not make the noise, but after a minute of being on plane it would rattle, we backed off throttle some and it would stop. In idle when reved up it does not make the noise.

My first thoughts are that the noise is detonation and that the timing needs checked, or the fuel he couldn't get out of the tank was bad and mixed with the fresh 10 gallons and wasn't always burning good. Check timing and put in 93 octane fuel.

I have a fear the head is possibly cracked or the manifold is cracked and that is also causing the noise, but I would imagine that it would ping/rattle/detonate every time it had a load placed. Not sure if it was me hoping it was better or if it did get better after we put a can of seafoam in the fuel.

Suggestions?

Ayuh,... I agree,... it's probably goin' Lean, from bad gas,...

 

[Jmunk]

Re: 3.0L pinging/detonation sound

Not sure if this has anything to do with the pinging but, the spark arrestor calls for MR43lts plugs and thats what we put in. Reading online it seems that those plugs are intended for the LX and he just has the 3.0L version. Are they the right plugs ?

 

[Jmunk]

Re: 3.0L pinging/detonation sound

Pulled spark plugs, #1 cylinder was lean, the plug was white and had a light layer of a white powder on it, the plugs were new before water test. The rest of the cylinders were good and looked to be running good.

Am I correct in thinking #1 cylinder is getting water in it since its the only cylinder running lean.

If it is water I'm thinking manifold is cracked on that cylinder or cracked head ? Is it common for the cylinder sleeves to crack when not winterized ? Double checked oil and no water.

 

[Bondo]

Re: 3.0L pinging/detonation sound

Pulled spark plugs, #1 cylinder was lean, the plug was white and had a light layer of a white powder on it, the plugs were new before water test. The rest of the cylinders were good and looked to be running good.

Am I correct in thinking #1 cylinder is getting water in it since its the only cylinder running lean.

If it is water I'm thinking manifold is cracked on that cylinder or cracked head ? Is it common for the cylinder sleeves to crack when not winterized ? Double checked oil and no water.

Ayuh,... I'm still thinkin' bad fuel,.... water would wash the plug, but not cause detonation,...
matter of fact, water injection has been used to fight detonation,...

If ya think there's a crack,(I don't, yet) pressure test the coolin' jacket,...

 

[Jmunk]

Re: 3.0L pinging/detonation sound

I need to look at the prop to find the stamping for the pitch. What the odds that a too high pitch would be causing this ?

 

[alldodge]

Re: 3.0L pinging/detonation sound

I need to look at the prop to find the stamping for the pitch. What the odds that a too high pitch would be causing this ?

The pitch of the prop will not cause your issue. A higher pitch prop then required will only slow you down and reduce performance.

 

[Don S]

Re: 3.0L pinging/detonation sound

Pulled spark plugs, #1 cylinder was lean, the plug was white and had a light layer of a white powder on it, the plugs were new before water test. The rest of the cylinders were good and looked to be running good.

Am I correct in thinking #1 cylinder is getting water in it since its the only cylinder running lean.

Water would make the plug look like it was brand new out of the box, no white power. Lean and water are not the same thing.

Not sure if this has anything to do with the pinging but, the spark arrestor calls for MR43lts plugs and thats what we put in. Reading online it seems that those plugs are intended for the LX and he just has the 3.0L version. Are they the right plugs ?

Yes, the MR43LTS is the correct plugs. The LX was last made in 97. Now all engines use the early LX style head and EST distributor.

You also might want to check your timing. Depending on your serial number of your engine, there was a 99 service bulletin that replace the flame arrestor decal. The old decal showed 1? ATDC as the timing, and the change was two 2? ATDC.

When you read something on the "internet" make sure it applies to your engine and serial number.

 

[Jmunk]

Re: 3.0L pinging/detonation sound

Is the 1 degree of timing that much of a difference ? On cars I have bumped timing a few degrees without changing fuel grades and no detonation. Any reason why the #1 cylinder would be lean, and the others looked good ?

 

[Don S]

Re: 3.0L pinging/detonation sound

On the 3.0L, it was the difference between blowing head gaskets and not blowing head gaskets.

You car doesn't run under full load at 4000 rpm for long periods of time.

 

[PeterB26]

Re: 3.0L pinging/detonation sound

Ethanol evaporates out of the gas rapidly. After sitting two years there probably isn't any ethanol left in the remaining gas.

Ethanol prevents knock. You won't get knock except under load so the boat runs fine on the muffs, but knocks under load in the water.

If you knew how much ethanol to add to bring the gas back to spec you could do that, but it how much? It isn't easy to guess.

Get rid of the old gas and top up with fresh. See if that doesn't fix your problem before you go messing about with other stuff.

Peter

 

[Jmunk]

Re: 3.0L pinging/detonation sound

Anyone have any idea why only the #1 plug is showing signs of running lean and the rest look good /

A few days ago, we pulled the head to inspect for cracks to the eye and checked headgasket. Everything looked good, cylinders all looked good too with no signs of a crack to the eye. Put new headgasket on, #1 piston was cleaner the rest, but looked good with no signs of pitting that i've seen in cars that ran lean and were run for a while. Put on a extra manifold that I had to rule out the old one being cracked. Ran good on the water for 20 min then started to ping again. My friend is losing motivation and about to sell. I'm half tempted to buy and see what I can do with it with a tank of fresh high octane and maybe a colder ranger set of plugs.

I didn't think was related but after reading this thread: http://forums.iboats.com/mercruiser...-3-0l-pings-above-3800-backfire-344122-2.html

The tach jumps around a lot and when cruising at a steady speed the tach is all over the place. In the above thread it had similar issues and bad coil, not sure how the coil would a noise like that ?

 

[Jmunk]

Re: 3.0L pinging/detonation sound

I think we are about done with this boat. After put in fresh 87 octane fuel the pinging/rattle noise is only present after its on plane and running at 3500 or so rpm. Should have put in high octane, but that's another story. I'm thinking the 93 octane should make a big difference, but in all the other 3.0L me and friends have had they ran fine on 87 octane.

Question: Is it common for the 3.0L to detonate on 87 octane ?
Also can anyone explain why only the #1 plug shows signs of being lean ?

 

[scottn83]

Re: 3.0L pinging/detonation sound

i have a similar issue minus the #1 cylinder issue its rattling at the 3500 have you checked the compression in each cylinder mine are a little low 90 90 120 and 90 for 1 thru 4 100 being the minimum. What is your WOT mine is at the 3500 range. I think mine may be either sticky valves or carb issues from talking to mult friends.

 

[tinkerguy70]

Re: 3.0L pinging/detonation sound

Question: Is it common for the 3.0L to detonate on 87 octane ?

I don't know if this helps, but mine doesn't detonate on 87 octane E10.

 

[Jmunk]

Re: 3.0L pinging/detonation sound

Compression is 160 all the way across. The tach is kinda all over the place at higher rpm, so not sure what the max rpm is currently.

Its a nice boat besides this issue and I'm not sure we will get it ironed out.

 

[Jmunk]

Re: 3.0L pinging/detonation sound

I don't believe that when we set the timing the engine rpm dropped when the shift interrupt wires were connected together. Which would mean the timing was not set right, and I suppose might cause this issue?

 

[price35]

Re: 3.0L pinging/detonation sound

I don't believe that when we set the timing the engine rpm dropped when the shift interrupt wires were connected together. Which would mean the timing was not set right, and I suppose might cause this issue?

My timing was just screwed up in my boat...too advanced and it was making a rattle sound...detonating...anyways thought it was fine... end result was a blown head gasket and started to burn the block....DON'T DRIVE IT TILL YOU GET IT FIXED!! My guy said if I drove it for any longer I would have blown the motor and needed a new block...It was 14 degrees too advanced