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Hi!  I have a 2013 250 SLX with...

Milan
Guest Contributor

Hi!  I have a 2013 250 SLX with mercruiser 350 MAG, I bought it 3.5 years ago and it only has 140 hours.  It sits on a lift above salt water and I have a direct flush kit which I use to flush the engine each time I use it.  Recently when at full throttle the guardian mode would get activated and would cut the throttle, but all engine indicators were good.  I had the marina hook it up to the laptop and they said it needs new manifolds and risers and maybe a new sensor.  I'm wondering how long manifolds and risers are normally lasting people in  saltwater environment when flushed properly. It's an expensive job and this seems kinda quick for only 140 hours on the boat so I'm curious if its really just the sensor but they are trying to upsell my service needs.  Thanks in advance.

2 REPLIES 2

wingless
Rising Contributor
Manifold corrosion is clearly visible once the elbow is unbolted from the manifold.

When the exhaust condition is acceptable, it is possible to grab / hold the manifold and elbow while the engine is operating. When corroded, the exterior exhaust temperature is much higher, making touching / holding the operating exhaust difficult.

If the exhaust has deteriorated w/ the flushing procedure described, then a procedure change is required. The expensive parts need to be protected.

When I flush my engines after salt water operation, I shut off the raw water, run the engines w/ fresh water, run the engines w/ soapy water, run the engines w/ Salt Away, then shut down. I then manually drain the manifolds bone dry.

My boat was designed to keep raw water in the bottom of the exhaust 24/7/365 w/ no way to flush. I redesigned the exhaust to permit the described flush / drain during the last replacement cycle because of the obscene parts cost and short OEM lifetime, about 3-4 years.

If the manifolds are degraded, then don't neglect the expensive service because engine failure is the expected result. There are lower cost aftermarket parts available. I have always used Mercruiser OEM parts.

Beez
Guest Contributor
Five years for risers and manifolds on a salt water-located lift. I flush religiously. You need a sinking fund which prepares you for the five-yearly bill.