Hi,
I have a 2002 Launch SSV with an Indmar Assault 350 / 5.7 TBI.
Yesterday when we were out with the boat we first spent a few minutes idling in gear. Then we throttled up and got on plane. Almost immediately I thought there was a strange noise and felt a vibration in the boat. We turned off the engine. Then started the engine again and idled in neutral for a while. Once we put the engine in gear the vibration and noise got worse. Hard to explain the noise. But a clunking maybe... We were towed to the dock where the boat is mooring.
Today I went down to do some troubleshooting and the engine starts right up but does run rough and I can hear a ticking/clicking noise from front of engine (towards the transom in the V-drive). I have pulled of the waterpump and belt (which have been squealing quite badly the last few outing, I had just gotten my replacement belt delivered). Noise is there without the waterpump as well.
I tried putting it in gear today and today I couldn't hear any difference with it in gear or out of gear.
I tried revving a bit and while the noise is not as apparent I would say it is most likely just because the engine is making more other (good kind of) sounds.
I started doing a compression test today and found that I had 170-185 on 3 of my 4 cylinders on port side of engine. The last one had 210. I could also see that there were some moisture on the plug. And this seemed to be water not fuel. I didn't continue with the starboard side of the engine as I wasn't sure I wanted to keep cranking the engine. The plugs were all black sooty, even the one that were wet. No rust at least.
Could this all be due to a bad manifold/riser gasket for example. Could that develop so quickly that all of sudden I would hear a strange noise even at 2500 + RPM? Or is this just another issue I found while checking for the root cause of my first problem? Not sure the running rough condition is actually what is causing my noise, but at least it should/could be causing my vibration.
Any input greatly appreciated!
A video with the noise:
https://www.dropbox.com/s/2spti3lkfo..._3617.MOV?dl=0
Thank you,
Mike