Formula thru hull W/ Silent Thunder
10-15-2017 | 09:18 AM
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Formula thru hull W/ Silent Thunder
This may be a cure for water reversion that I discovered. Boat had BB`s and now has standard 6.2`s nothing exotic. Thru hull with shutters and the Silent Thunder swim platform exaust.Motors have been plagued with reversion issues since the motors were installed.Cannot raise the riser with extentions because of the hatch, dry headers are not an option, lowering the exaust is not an option.
I post some pics when I can but the stbd motor was removed and rebuilt and returned to service with new dry joint manifolds, 3 inch extentions and risers.. . Motor ran all of 2016 with no reported problems, Fall of 2016 port motor removed for rebuilding.In spring of 2017 port motor returned to service and when starting the stbd motor stuck valves were found. Manifolds, extentions and risers found heavily rusted and exaust ports rusted . Heads R/R .Boat returned to service.
On the return trip port motor would not develop power and was backfiring. Now this motor has about a hour of run time for breakin. Compressin test revealed 2 dead pistons and 3 weak cylinders.Teardown found the same rusty conditions. Heads R/R
While waiting for heads I removed the stbd riser for inspection and found this
This is with 1 1/2 hour run time .So after some inspection the top of the riser is 15 inches above the water level, shutters are in place and operational, swim platform has 6 extra 5 inch holes in the bottom .So the only answer we could come up with was extending the outlet of the riser. 2 inch OD thinwall SS tubing is a perfect hammer in fit.Not knowing the length needed I went with 12 inch tubes hammered in 2 1/2 inches. Advised customer that we might burn a hole thru the wet exaust because of the length of the tube resting on the bottom of the exaust tube. And we did but there was no indication of any salt deposits, the manifolds and risers were a nice shade of black.,so tubes shortened 2 inches.
Another weekend and after 5 hours no reported issues so this may be the cure and will have new pics at end of season. This pic is the original length of the tube that was used. How long do they need to be is unknown but it did stop the reversion
I post some pics when I can but the stbd motor was removed and rebuilt and returned to service with new dry joint manifolds, 3 inch extentions and risers.. . Motor ran all of 2016 with no reported problems, Fall of 2016 port motor removed for rebuilding.In spring of 2017 port motor returned to service and when starting the stbd motor stuck valves were found. Manifolds, extentions and risers found heavily rusted and exaust ports rusted . Heads R/R .Boat returned to service.
On the return trip port motor would not develop power and was backfiring. Now this motor has about a hour of run time for breakin. Compressin test revealed 2 dead pistons and 3 weak cylinders.Teardown found the same rusty conditions. Heads R/R
While waiting for heads I removed the stbd riser for inspection and found this
This is with 1 1/2 hour run time .So after some inspection the top of the riser is 15 inches above the water level, shutters are in place and operational, swim platform has 6 extra 5 inch holes in the bottom .So the only answer we could come up with was extending the outlet of the riser. 2 inch OD thinwall SS tubing is a perfect hammer in fit.Not knowing the length needed I went with 12 inch tubes hammered in 2 1/2 inches. Advised customer that we might burn a hole thru the wet exaust because of the length of the tube resting on the bottom of the exaust tube. And we did but there was no indication of any salt deposits, the manifolds and risers were a nice shade of black.,so tubes shortened 2 inches.
Another weekend and after 5 hours no reported issues so this may be the cure and will have new pics at end of season. This pic is the original length of the tube that was used. How long do they need to be is unknown but it did stop the reversion
