Bt Doctur
Well-Known Member
Hello boaters, a new member with a old problem. Trying to find the answer to this problem for the owner.Boat had BB motors are they were removed for 6.2 SB W/ 3 inch riser extentions. When first serviced for a bad starter we found the manifolds heavily rusted .Motor is very poor condition and it was pulled for a rebuild at the end of 2015. For 2016 no reported problems and was winterized. Fall of 2016 port motor pulled for rebuild, same conditions of the manifold. Heavily rusted but no water in the oil.
Fast forward to spring of 2017. New port motor installed and tested on land 2X. stbd motor started and it had some stuck valves.
??
Removed heads and they were just ugly. No issues found in the heads and motor was new so new heads installed.Boat put in service.
2 hours later port motor takes a dump. 3 valve hung wide open
?
Shop keeps saying water ingestion but oil remains clean so we then suspect exaust reversion. Cannot raise the risers or use dry headers,
cannot lower the exaust or swim platform so we did the next best thing , extended the riser outlet.Not knowing how long they should be I used 12 inch tubes hammered in 2 inches leaving 10 inches exposed.
The manifold and riser pics shown only have about 2 hours run time and were loaded with what looked like rocksalt debris. So being a test engine were guessing on the length. The tubes are 2 inch OD SS thin wall 12 inches long .Our "Think Tank" says it should work to prevent the reversion .If this is true I should find nothing but carbon in the manifolds and risers when I remove one for inspection at the end of this season.
Stay tuned for a update and pictures soon
An Update 4 hours run time at power
Burned a small hole thru the exaust hose but it was expected because I`m in uncharted waters with the length of the tubes. Remove the risers and shortened then 2 inches and repaired the hole for now. You could see where the tube was pushing down on the hose because it was shiny clean.
The good news is there was no sign of any moisture and the manifolds, the extention or the risers .There was a nice black coat of carbon deposits and no white salt residue.
Finally some sucess. Pics at the end of this season
Fast forward to spring of 2017. New port motor installed and tested on land 2X. stbd motor started and it had some stuck valves.
Removed heads and they were just ugly. No issues found in the heads and motor was new so new heads installed.Boat put in service.
2 hours later port motor takes a dump. 3 valve hung wide open
Shop keeps saying water ingestion but oil remains clean so we then suspect exaust reversion. Cannot raise the risers or use dry headers,
cannot lower the exaust or swim platform so we did the next best thing , extended the riser outlet.Not knowing how long they should be I used 12 inch tubes hammered in 2 inches leaving 10 inches exposed.
The manifold and riser pics shown only have about 2 hours run time and were loaded with what looked like rocksalt debris. So being a test engine were guessing on the length. The tubes are 2 inch OD SS thin wall 12 inches long .Our "Think Tank" says it should work to prevent the reversion .If this is true I should find nothing but carbon in the manifolds and risers when I remove one for inspection at the end of this season.
Stay tuned for a update and pictures soon
An Update 4 hours run time at power
Burned a small hole thru the exaust hose but it was expected because I`m in uncharted waters with the length of the tubes. Remove the risers and shortened then 2 inches and repaired the hole for now. You could see where the tube was pushing down on the hose because it was shiny clean.
The good news is there was no sign of any moisture and the manifolds, the extention or the risers .There was a nice black coat of carbon deposits and no white salt residue.
Finally some sucess. Pics at the end of this season