wajetter
Jet Boat Lover
- Messages
- 67
- Reaction score
- 26
- Points
- 67
- Boat Make
- Yamaha
- Year
- 2006
- Boat Model
- AR
- Boat Length
- 23
Back in 2023 my port MR1 HO spun a rod bearing. Replaced it along with crank and it lasted the season. Next summer the same engine had a piston crack. So this spring I did a complete overhaul
- WSM pistons and rings .25 overized
- Block bored and honed to .25 match
- Some new crank bearings (some were out of spec - too large when plastic gauged)
- checked rod bearings in spec
- rebuilt the head: new valves, chain, guides, checked and shimmed valves properly per spec
Filled up 4.5 QTs of 10-40 Yamalube conventional and started break in. Kept seeing oil level go down, so over the first couple hours ended up adding 0.75 qt overall.
Today on be lake, heard a pop and watched rpm start dropping.
The engine has a tapping noise and some knocking, but not the type of knocking when a rod bearing goes bad.
I then, at some point oil pressure light came on. But, there is enough oil and there are no external leaks visible.
So, I am concerned that the oil pump is bad and has given me disservice for 3rd time now. It was inspected during the rev build, the mesh cleaned (the result of piston grenading.
The oil itself is getting darker sooner than expected. Before the knock, when revved with intake cover off, I could see blow by smoke appear. The other engine (starboard) is healthy - also was completely rebuilt for another reason (water got past the gasket that holds the cooling water going into the head, so hydro locked and cracked head when attempted to start in spring).
So, a little depressing here after a couple months and several thousand spent rebuilding only to have the port go bad after a few hours of fun.
I am seeing pump rebuild kits - are they a good option vs a new or used oil pump?
/rant
- WSM pistons and rings .25 overized
- Block bored and honed to .25 match
- Some new crank bearings (some were out of spec - too large when plastic gauged)
- checked rod bearings in spec
- rebuilt the head: new valves, chain, guides, checked and shimmed valves properly per spec
Filled up 4.5 QTs of 10-40 Yamalube conventional and started break in. Kept seeing oil level go down, so over the first couple hours ended up adding 0.75 qt overall.
Today on be lake, heard a pop and watched rpm start dropping.
The engine has a tapping noise and some knocking, but not the type of knocking when a rod bearing goes bad.
I then, at some point oil pressure light came on. But, there is enough oil and there are no external leaks visible.
So, I am concerned that the oil pump is bad and has given me disservice for 3rd time now. It was inspected during the rev build, the mesh cleaned (the result of piston grenading.
The oil itself is getting darker sooner than expected. Before the knock, when revved with intake cover off, I could see blow by smoke appear. The other engine (starboard) is healthy - also was completely rebuilt for another reason (water got past the gasket that holds the cooling water going into the head, so hydro locked and cracked head when attempted to start in spring).
So, a little depressing here after a couple months and several thousand spent rebuilding only to have the port go bad after a few hours of fun.
I am seeing pump rebuild kits - are they a good option vs a new or used oil pump?
/rant
