Soot from exhaust!

[Forfatsnakes]

Can anyone tell me why I have soot coming out of my ysm8 exhaust? It runs ok for an underpowered engine ! But I leave a residue of soot on the water as I go , not oil , anyone know what could be the cause please ?

 

[dankilb]

Blocked exhaust elbow? Have you removed to inspect recently?

 

[Forfatsnakes]

I will certainly give it a go . Thanks !

 

[neil_s]

It may be that your engine is over-propped and is generating black smoke that is being 'washed' by the cooling water. You say it's under-powered, maybe the prop is not the correct size to allow it to get to full RPM. As dankilb says above - a blocked up exhaust elbow might also give those symptoms.

 

[Boater Sam]

Can anyone tell me why I have soot coming out of my ysm8 exhaust? It runs ok for an underpowered engine ! But I leave a residue of soot on the water as I go , not oil , anyone know what could be the cause please ?

Its only a 4kw engine, if it is overloaded it will produce black carbon smoke and hence soot. If the injector is not atomising properly it will also smoke.

 

[jwfrary]

First look for build up of weed or barnacles on the prop or bottom of the boat. Also check theres no tightness in the shaft line.

If that's ok then, Try some liquid moly diesel purge on the injector.

Exhaust elbows are always worth a periodic check with or without symptoms.

Occasionally wet exhaust hose has been known to fail internally and produce similar symptoms to a blocked elbow.

 

[Forfatsnakes]

It may be that your engine is over-propped and is generating black smoke that is being 'washed' by the cooling water. You say it's under-powered, maybe the prop is not the correct size to allow it to get to full RPM. As dankilb says above - a blocked up exhaust elbow might also give those symptoms.

I will check the exhaust elbow tomorrow, I only have a small 2 blade prop on her , I will try anything , it's embarrassing, even ticking over .

 

[Forfatsnakes]

First look for build up of weed or barnacles on the prop or bottom of the boat. Also check theres no tightness in the shaft line.

If that's ok then, Try some liquid moly diesel purge on the injector.

Exhaust elbows are always worth a periodic check with or without symptoms.

Occasionally wet exhaust hose has been known to fail internally and produce similar symptoms to a blocked elbow.

Thanks for that , I will certainly check all those .

 

[Oily Rag]

Check for a blockage in the air filter housing. Or a blocked air filter.

 

[dankilb]

even ticking over

This does sound more suspicious than just ‘blowing coal’ under heavy load (as the diesel car tuner/truck pull lot call it!)

But chase it through the system, as you advised above - Air in (filter)? Exhaust out (elbow/hose)? Or fuel (injectors)?

Gotta love diesels