VMAX 150 Engine Noise

[crf28]

Just got back from a four day trip. At idle, my engine has a "ticking" noise regardless if it is in gear or not. The noise seems to drown itself out after about 1300 RPMs. I don't know if it is still there after 1300 or not as the wind noise, engine noise, etc, becomes louder as I increase speed. The engine does not idle rough, no loss of power or acceleration, the oil pump is still working, no increase in fuel consumption, just this "ticking". Pulled all spark plugs, none fouled or leaned out. The noise does not seem like a knocking in the engine to indicate a rod, bearing, etc, is going bad. The closest thing I can relate to the noise would be like something similar to that of a slight valve ping or even better an exhaust gasket leak. Im leaning towards the exhaust leak as the pressure as the RPM"s increase would most likely (with a small gasket leak) pass by this leak and follow the larger exhaust ports. Any ideas guys?

[iron banks]

Believe I remember that sound in my old carbed 150 v-max.

[185DVS]

I had a noise very similar to what you are describing and found that it was the small barbell type tube that passes the exhaust gas from the head to the O2 Sensor.The tube was Partially blocked with carbon deposits even though I had always used Ringfree with every gallon of gasoline. Cleaned the tube and O2 Sensor and switched from Ringfree to Seafoam and the problem has not returned in about three years. Hope this helps you with your diagnosis. I was able to pinpoint the noise using a screwdriver as a substitute for a stethascope.

[crf28]

As a result of the suggestion by 185, I removed the O2 sensor, cleaned the joint, cleaned ALL of the carbon deposits and installed with new gaskets. Started up today and did not hear any ticking. Thanks for the suggestion.........cost..$17.00!

[mduncan62]

That is good news. I have the same motor, and was wondering if you knew what the max RPM is on this motor. I haven't been able to find anything. I run 5200 wide open with a 25m Prop. Was wondering if I can get more out of it and remain within the max range.

Thanks in advance.

[fishnhunt]

5200 is low should be around 5600 WOT RPMS. Come up with your engine. I reccomend trying a 23 pitch prop!

[Z518 Comanche]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by fishnhunt &raquo;</td></tr><tr><td class="quote">5200 is low should be around 5600 WOT RPMS. Come up with your engine. I reccomend trying a 23 pitch prop! </td></tr></table> I run a 23m. Rpm's are 5800.

[mduncan62]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Skeeter ZX-190 &raquo;</td></tr><tr><td class="quote"> I run a 23m. Rpm's are 5800. </td></tr></table>

So is 5800 the max? I'm going to track down a 23m prop.

Thanks for the help guys.

[Mat_HT]

rev-limiter is aat 6150. prop it to run in the upper 5's and you will be good. anything under 5500 will put an excessive amount of load on the engine, and with continuous use could damage the motor.

[mduncan62]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by Mat_HT &raquo;</td></tr><tr><td class="quote">rev-limiter is aat 6150. prop it to run in the upper 5's and you will be good. anything under 5500 will put an excessive amount of load on the engine, and with continuous use could damage the motor.
</td></tr></table>

Thank you.

Just ordered a 23 from a guy on here. I'll test it out and see where it puts me at.

[fishin couillon]

Wish you were closer, would like to try that 25 on mine.

[mduncan62]

The 25 does pretty good in winter, but not so good once the water warms up.

[fishin couillon]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by mduncan62 &raquo;</td></tr><tr><td class="quote">The 25 does pretty good in winter, but not so good once the water warms up.
</td></tr></table>That's what i was thinking especially down here.

[mduncan62]

Good idea to have a winter prop, and a rest of the year prop. Some people only need a spare, but where the water gets in the 30's and below you need to different pitches.