Ocean Toad
Recruit
- Joined
- Jul 13, 2018
- Messages
- 2
!981 Mercruiser 485, was running great, Boat sat for a week, now it runs great in the driveway hooked to a hose but bogs and starts missing under load at about 2000 rpm in the water. Acts like it is going to blast off at first. I replaced the out-drive earlier this year. Was going to rebuild the carb but replaced it with a Edelbrock, that was working great. Pink springs and stock jets worked best. Tests I have performed and things I have tried.
Replaced both fuel filters.
Checked fuel flow, 1 quart in 13 seconds, (electric fuel pump)
Tried removing pressure regulator, put back and checked pressure setting. Set at 5 PSI. Per Edelbrock specs.
Checked fuel pressure under load and it is steady at 5 psi.
Cleaned and blew out all passages in new Edlebrock carb, double checked float level.
Tried running engine off can of fresh gas, after draining fuel filter, lines and carb.
Tried moving accelerator pump setting to biggest shot. It liked that.
Replaced carb to manifold gaskets and carb spacer with a new one even tho old one checked flat with my machinist straight edge.
Tired running it without spark arrestor.
Replaced Pertronix ignitor and coil.
Replaced Distributor cap and rotor,
Replaced plug wires and and plugs.
Checked timing and total timing advance
Removed distributor and disassembled and checked advance was working freely.
Checked voltage to distributor.
Checked it was firing regularly with timing light under load.
Changed oil and looked for metal.
Did a compression test. 155 - 165 all.
Pulled off valve cover and found no sign of water in the oil and everything looked copacetic.
Pulled exhaust manifold off and found no blockage or signs of leaking.
Ran my little camera down the exhaust to the out-drive, no blockage to transom.
I am hoping maybe someone has run into something like this before and could enlighten me.
Replaced both fuel filters.
Checked fuel flow, 1 quart in 13 seconds, (electric fuel pump)
Tried removing pressure regulator, put back and checked pressure setting. Set at 5 PSI. Per Edelbrock specs.
Checked fuel pressure under load and it is steady at 5 psi.
Cleaned and blew out all passages in new Edlebrock carb, double checked float level.
Tried running engine off can of fresh gas, after draining fuel filter, lines and carb.
Tried moving accelerator pump setting to biggest shot. It liked that.
Replaced carb to manifold gaskets and carb spacer with a new one even tho old one checked flat with my machinist straight edge.
Tired running it without spark arrestor.
Replaced Pertronix ignitor and coil.
Replaced Distributor cap and rotor,
Replaced plug wires and and plugs.
Checked timing and total timing advance
Removed distributor and disassembled and checked advance was working freely.
Checked voltage to distributor.
Checked it was firing regularly with timing light under load.
Changed oil and looked for metal.
Did a compression test. 155 - 165 all.
Pulled off valve cover and found no sign of water in the oil and everything looked copacetic.
Pulled exhaust manifold off and found no blockage or signs of leaking.
Ran my little camera down the exhaust to the out-drive, no blockage to transom.
I am hoping maybe someone has run into something like this before and could enlighten me.
