puzzolente
Member
"Hello all, I started a thread
"Hello all, I started a thread a few weeks ago about the lack of power from my 91 350 mag, I'm really sorry to bother you again I'm really struggling!! I'm not mechanically gifted so I've got my mechanic helping me and now he's completely stuck! As a bit of background we've done the following:
Full Service
New plugs/leads/thunderbolt module/dizzy cap
Full outdrive overhaul (Alpha 1)
Stripped/overhauled carb. (rochester)
The engine runs perfectly, all temps/oil press. are great but as soon as it's under load it has no grunt at all, I can just about get 2800 RPM and at full throttle the revs just die off until I can only get 2000rpm, if i throttle off and open it up again, it will get about 2800rpm then it will die off again!! I've swapped props (19" and 20") and it's made no difference, the boat was laid up for 5 years with quite a bit of fuel, I've since put about 150 litres in it and I'm assuming the old stuff has now gone through as I've used it quite a lot! We've been out and altered the timing at sea advancing it as much as possible and it's made no difference, how sensitive are these engines to timing?? 2 Weeks ago I took the sundeck off (very heavy) just to be sure the weight of it wasn't causing problems and took it out, pulled 3750 rpm with the bigger prop but it was pinking so we retarded the ignition slightly, put the sundeck back on and now we're back to square one!
In the UK really good knowledge of these engines is very hard to come by (at a sensible cost!!) so forgive me once again but any advice would be hugely appreciated.
Regards
Mark"
"Hello all, I started a thread a few weeks ago about the lack of power from my 91 350 mag, I'm really sorry to bother you again I'm really struggling!! I'm not mechanically gifted so I've got my mechanic helping me and now he's completely stuck! As a bit of background we've done the following:
Full Service
New plugs/leads/thunderbolt module/dizzy cap
Full outdrive overhaul (Alpha 1)
Stripped/overhauled carb. (rochester)
The engine runs perfectly, all temps/oil press. are great but as soon as it's under load it has no grunt at all, I can just about get 2800 RPM and at full throttle the revs just die off until I can only get 2000rpm, if i throttle off and open it up again, it will get about 2800rpm then it will die off again!! I've swapped props (19" and 20") and it's made no difference, the boat was laid up for 5 years with quite a bit of fuel, I've since put about 150 litres in it and I'm assuming the old stuff has now gone through as I've used it quite a lot! We've been out and altered the timing at sea advancing it as much as possible and it's made no difference, how sensitive are these engines to timing?? 2 Weeks ago I took the sundeck off (very heavy) just to be sure the weight of it wasn't causing problems and took it out, pulled 3750 rpm with the bigger prop but it was pinking so we retarded the ignition slightly, put the sundeck back on and now we're back to square one!
In the UK really good knowledge of these engines is very hard to come by (at a sensible cost!!) so forgive me once again but any advice would be hugely appreciated.
Regards
Mark"