richardson61
Seaman Apprentice
- Joined
- Oct 3, 2008
- Messages
- 39
Been pulling my hair out trying to solve a small problem with our boat. Purchased and installed a rebuilt short block over the winter. Everything went fine and was running good during the break in period. Its a 93 SeaRay with a 4.3L.
After break in and we could take it over 400 rpm's we have notice a knock or pop at around 4200 rpm's never does it before can run all day at 4000. It never does it on take off when demand is highest and will develop say 30 secs or so once 4200 rpm's is reach and pop ever 10 or 15 secs, but always back it off after one or 2 pops.
As part of the rebuild we install a new Delco Voyager distributor, finding the correct timing setting has been an issue but after several talks with the head tech where we purchased the engine, 4 degrees seems to be the correct one. Under his advise I have tried changing it from 8 to -6 going one degree at a time, and have the same results at same rpms.
Its also not reaching the recommended WOT, which for this boat is 4800, its maxing out at the 4200. We are using same prop size and pitch that we use on the old motor and it reached 4800 with no problem at all.
Have changed plugs a couple times, first set where nice and tan, second set had a some black soot on them, we have switched to a higher octane fuel which I thought might be causing this. Have changed fuel filter and water seperator filter. Checked fuel for water seems to be none.
After break in and we could take it over 400 rpm's we have notice a knock or pop at around 4200 rpm's never does it before can run all day at 4000. It never does it on take off when demand is highest and will develop say 30 secs or so once 4200 rpm's is reach and pop ever 10 or 15 secs, but always back it off after one or 2 pops.
As part of the rebuild we install a new Delco Voyager distributor, finding the correct timing setting has been an issue but after several talks with the head tech where we purchased the engine, 4 degrees seems to be the correct one. Under his advise I have tried changing it from 8 to -6 going one degree at a time, and have the same results at same rpms.
Its also not reaching the recommended WOT, which for this boat is 4800, its maxing out at the 4200. We are using same prop size and pitch that we use on the old motor and it reached 4800 with no problem at all.
Have changed plugs a couple times, first set where nice and tan, second set had a some black soot on them, we have switched to a higher octane fuel which I thought might be causing this. Have changed fuel filter and water seperator filter. Checked fuel for water seems to be none.
