8.1 Horizon knocking sound

[jmauld]

Yes to all that

The sea foam worked great on the little four cylinder turbo engines for about a year. Those engines dumped fuel like crazy to keep temps down. Which caused a lot of buildup.

1) pour directly into cylinder heads

2) pour into the oil

3) pour into the pvc inlet

you’d smoke out the neighborhood for a good 20 minutes. Change the oil and it would cure the lifter tick for a while.

those engines were $1500. I don’t think I’d do this on a $15,000 engine. But maybe if one of you guys did it first. Also you will likely have the fire department called on you if you do this on the water or at a dock.

 

[sejensen737]

Thanks I will replace wires. Plugs were done @100 hours ago w/platinum AC 's.
The knock seems to be sporadic and short lived, always just during start up and first 30 seconds. Another thing I might do is dose the engine with a Seafoam cocktail directly into fuel lines. That should help clean and lubricate lifters.

I get it. My plugs were AC platinum's with 30 hours on them. That is one reason I put them on the bottom of my list of possible causes of my problem. I wasted tons of time going down dead end rabbit holes. Turns out 5 of them went bad in very short order. Still a mystery as to why...
Also , my engine knocked as it was cranking and trying to start , scaring the shite out of me that I had a serious , deeper problem. It has been starting/running perfectly since plugs were replaced.

 

[jmauld]

I get it. My plugs were AC platinum's with 30 hours on them. That is one reason I put them on the bottom of my list of possible causes of my problem. I wasted tons of time going down dead end rabbit holes. Turns out 5 of them went bad in very short order. Still a mystery as to why...
Also , my engine knocked as it was cranking and trying to start , scaring the shite out of me that I had a serious , deeper problem. It has been starting/running perfectly since plugs were replaced.

Was there a lot of build up on the plugs? If so you might try cleaning your injectors.

 

[sejensen737]

Was there a lot of build up on the plugs? If so you might try cleaning your injectors.

Plugs were not badly carboned up. Injectors had been cleaned the year before.

 

[jmauld]

Bummer, that would be an easy fix.

if it’s like everything else with these motors, it’s probably a bad sensor.

 

[Pilot]

Well I haven’t had time to seafoam the engines yet but, the knocking has stopped. I think it may have been a combination of old gas and not running it enough. I will still do the seafoam soon and report back.