hey guys im really Stuck with my own boat.
My boat is a 18 foot deep v boat with a mercruiser 470 that is freshly rebuilt.
Ater the rebuild the engine would rev up to 5000 rpm no problem, then one day i took it on the lake and tried wot and it would go to 4200 rpm and stay there and just make alot of noise but not go anywhere. That last bit of throttle i backed off and the intake noise would be less loud, so the last quarter throttle would just go up to 4200 rpm and just make noise after that. Then i decided to upgrade all the ignition parts to better wires, electronic points system, flame thrower coil. Ok now for a test drive .... same thing max rpm 4200 and no one home for that last quarter of the throttle. I then checked my fuel system and replace the fuel pump and changed all the lines, removed the check vave from the tank to the filter, changed fuel filter. Test drive time....... grrrrrr same thing. OK time for more upgrades since im at it, 4bbl intake manifold with carb from a 3.7 190 hp engine, rollerized rockers changed the camshaft, changed to a new distributor, and now i have a super new engine with alot of upgraded parts..... TEST DRIVE TIME! SAME thing but if i leave it at wot for maybe 30 seconds then i see the rpm creep from 4200 to 4300rpm then all of a sudden after 4300 rpm it takes off like a rocket and revs up to 5200 with so much top end power due to the upgrades and i was like holly smokes.... backed the throttle off a bit and rpms dropped below 4200 and same thing ... wont rev past 4200rpm unless i keep it full throttle for more then 30 secs... sometimes it wont even rev past 4200 rpm ... IAM STUMPED .... if any one could help me with this that would BE great... oh yeah one more thing i have removed the exhaust to see if the shutter got launched in the exhaust system ... it was all there no exhaust restrictions .....
My boat is a 18 foot deep v boat with a mercruiser 470 that is freshly rebuilt.
Ater the rebuild the engine would rev up to 5000 rpm no problem, then one day i took it on the lake and tried wot and it would go to 4200 rpm and stay there and just make alot of noise but not go anywhere. That last bit of throttle i backed off and the intake noise would be less loud, so the last quarter throttle would just go up to 4200 rpm and just make noise after that. Then i decided to upgrade all the ignition parts to better wires, electronic points system, flame thrower coil. Ok now for a test drive .... same thing max rpm 4200 and no one home for that last quarter of the throttle. I then checked my fuel system and replace the fuel pump and changed all the lines, removed the check vave from the tank to the filter, changed fuel filter. Test drive time....... grrrrrr same thing. OK time for more upgrades since im at it, 4bbl intake manifold with carb from a 3.7 190 hp engine, rollerized rockers changed the camshaft, changed to a new distributor, and now i have a super new engine with alot of upgraded parts..... TEST DRIVE TIME! SAME thing but if i leave it at wot for maybe 30 seconds then i see the rpm creep from 4200 to 4300rpm then all of a sudden after 4300 rpm it takes off like a rocket and revs up to 5200 with so much top end power due to the upgrades and i was like holly smokes.... backed the throttle off a bit and rpms dropped below 4200 and same thing ... wont rev past 4200rpm unless i keep it full throttle for more then 30 secs... sometimes it wont even rev past 4200 rpm ... IAM STUMPED .... if any one could help me with this that would BE great... oh yeah one more thing i have removed the exhaust to see if the shutter got launched in the exhaust system ... it was all there no exhaust restrictions .....