Glowing exhaust, cuts out at 3200

[Sparkster]

Hello all.
Im trying to analyze a problem with the starboard engine in a 2019 Yamaha AR210. The engine is a TR1. Engine Family KYMXM1.054GG. It wanted to cut out at around 3200 RPM and the Stainless exhaust outlet was glowing red. Water was still pissing out the telltale. It got shut down and was still glowing red, so fire extinguishing agent was shot at it. So far the troubleshooting has just been pulling the plugs and comparing to the starboard engine plugs. They all look good and have recently been replaced. The engine has very low hours on it (I think less than 50). There was a mod done to the cooling system that added a valve to the water intake before it splits to engine and exhaust. The purpose of this is to be able to shut off the water intake when running on one engine so there is no chance of water ingestion into the engine that is not running through the exhaust. Wondering about a dead cylinder dumping raw fuel into the exhaust that got ignited. I might swap coils, then injectors and see if the problem follows. Appreciate any insight from you who have run these. Have not yet done a compression test or cylinder leakdown but probably will.

 

[Cobra Jet Steering LLC]

the water line to your exhaust is blocked

 

[FSH 210 Sport]

Sounds like the water flow to the exhaust manifold has stopped.

 

[buckbuck]

There have been reports that adding those valves decrease the amount of flow of cooling water. I would start there by removing it and see if it continues. That manifold should be getting most of the water flow. Keep us posted.

 

[Sparkster]

I pulled the water inlet valve that was added as a mod. It is a ball valve that opens completely up so it so that its passage looks to be no smaller than the reduction that you get with any of the other barbed nipples in the system. I'm not completely ruling it out, but it certainly looks like it doesn't add any restriction other than one more straight barbed union would add (just the wall thickness of a fitting). It looks as if there are 3 places where water lines attach to the exhaust. Next step I think is to check all for restrictions.