Pinging noise at WOT, ideas

[2005Vip]

OK new problem, isn't boat ownership fun...:laugh: Got the boat out on the lake today and it ran great except that when I hit 3800 - 4000 rpm's it was making a pinging noise. I'll try to explain it the best I can. It was not a ticking, but more of a "metal like pinging" noise that lasted about a half second. It doesn't make the noise at lower rpm's, but was fairly consistent at making it close to WOT. It was inconsistent in it's timing, not rhythmic. The higher the rpm's the more likely I was to get the noise. I could not pin point where the noise was coming from in the engine.

Do you think it is a valve problem, low octane fuel, timing etc?

The previous owner said that he did a annual tune up on it this year(cap, rotor, plugs, carb kit, oil). I'm not sure if maybe he did something incorrectly? Any help would be helpful. My great deal I got on this boat is slowly turning into a break even situation which still isn't bad. Unless this keeps happening every week, :facepalm:.

Thanks!

 

[tank1949]

Re: Pinging noise at WOT, ideas

If that is wot, then something is off. Motor trimmed out should hit at least 4200. Highly suggest do compression on all cyl. Sounds like not propped right or something bad.

 

[NHGuy]

Re: Pinging noise at WOT, ideas

Ping comes from over advanced timing. Engine ping is really bad on the motor internals, don't run it to those RPMs til the timing is checked and set to spec.

 

[bonzoscott]

Re: Pinging noise at WOT, ideas

Detonation is constant once established at the RPM. Lasting only 1/2 second doesn't make sense. How many times have you listened for this noise at the said RPM? If you're not familiar with detonation (pinging), yes it would be hard to pin point the noise if it's intermittent. Only other thought is a lifter floating at high RPM. What is your oil pressure at 3500-4000 RPM?

 

[thumpar]

Re: Pinging noise at WOT, ideas

Ping comes from over advanced timing. Engine ping is really bad on the motor internals, don't run it to those RPMs til the timing is checked and set to spec.

That is where I would start.

 

[2005Vip]

Re: Pinging noise at WOT, ideas

If that is wot, then something is off. Motor trimmed out should hit at least 4200. Highly suggest do compression on all cyl. Sounds like not propped right or something bad.

I had my wife and two kids in the boat and could easily get to 4600 rpm's, but I keep it low due to the noise.

 

[2005Vip]

Re: Pinging noise at WOT, ideas

Detonation is constant once established at the RPM. Lasting only 1/2 second doesn't make sense. How many times have you listened for this noise at the said RPM? If you're not familiar with detonation (pinging), yes it would be hard to pin point the noise if it's intermittent. Only other thought is a lifter floating at high RPM. What is your oil pressure at 3500-4000 RPM?

Right at 40lbs

 

[2005Vip]

Re: Pinging noise at WOT, ideas

I took the boat into the shop to get a yoke seal replaced and they found the problem. The head gasket was blown.

 

[Bondo]

Re: Pinging noise at WOT, ideas

I took the boat into the shop to get a yoke seal replaced and they found the problem. The head gasket was blown.

Ayuh,.... I'd sooner think they found the Results, 'n Not the cause,....

Yer experincin' Detonation, probably from a Lean condition,...

 

[2005Vip]

Re: Pinging noise at WOT, ideas

Ayuh,.... I'd sooner think they found the Results, 'n Not the cause,....

Yer experincin' Detonation, probably from a Lean condition,...

You could tell by a partially melted plastic part by the impeller that it had over heated at one point. so hopefully after this and setting up he timing I'll be set.