The boat is a 85 century 5000 sun express, the engine is a 5.0 litre v8 with a stringer 800 stern drive, max capacity is 9 persons or 1650 lbs 3090 lbs persons and gear I don't know if the boat is classified as a heavy cruiser or not I would say its more like a weekender mostly cabin with a small area in back for sitting, the engine has been tuned last season new distributor, spark plugs, spark plug wires, timing was checked and adjusted and runs well, all fluids changed in the stern drive, the bottom of boat is clean with no debris so no drag there. I have had this boat for 2 years and have never had more than 2 adults onboard till this season, with 2 adults it will plane and still max rpms at wot is still no more than 3100 rpm but there seems to be a strain on the engine before planning. I have checked the trim tabs and they seem to be working they both move up and down fully, I checked the throttle cable and the cable opens the carb. fully at full throttle so its not that, I have also tried distributing the weight of the passengers 2 in the cabin 2 in the rear the rpms changed slightly and you can hear the engine not struggle as much but not enough to make a difference. The previuos owner told me that it took awhile to get on plane but once on plane it cruises nice that seems to be true as long as there is only 2 or 2 adults onboard. I was told by a marina mechanic I spun the prop and it needs to be replaced but that doesn't sound right to me.dazioman said:
The boat is a 85 century 5000 sun express, the engine is a 5.0 litre v8 with a stringer 800 stern drive, max capacity is 9 persons or 1650 lbs 3090 lbs persons and gear I don't know if the boat is classified as a heavy cruiser or not I would say its more like a weekender mostly cabin with a small area in back for sitting, the engine has been tuned last season new distributor, spark plugs, spark plug wires, timing was checked and adjusted and runs well, all fluids changed in the stern drive, the bottom of boat is clean with no debris so no drag there. I have had this boat for 2 years and have never had more than 2 adults onboard till this season, with 2 adults it will plane and still max rpms at wot is still no more than 3100 rpm but there seems to be a strain on the engine before planning. I have checked the trim tabs and they seem to be working they both move up and down fully, I checked the throttle cable and the cable opens the carb. fully at full throttle so its not that, I have also tried distributing the weight of the passengers 2 in the cabin 2 in the rear the rpms changed slightly and you can hear the engine not struggle as much but not enough to make a difference. The previuos owner told me that it took awhile to get on plane but once on plane it cruises nice that seems to be true as long as there is only 2 or 2 adults onboard. I was told by a marina mechanic I spun the prop and it needs to be replaced but that doesn't sound right to me.QC said:
QC said:Is this your boat?
Does look pretty heavy . . . I have actually found 2 on the net. Both have 5.7s and trim tabs. Proper use of trim tabs may get you over on plane with the heavier loads, but I am assuming you are putting the tabs in the down position to help get her on plane. RPM numbers are still very low though. Are you sure the tach is reading correctly? There is a switch behind most of them for 4, 6 or 8 cyl. Make sure that is correct. If the tach is right, the bottom is clean and it is truly running right, then yes you need to reduce pitch. However, based on your RPM numbers you need to go down a LOT. Like to a 13 or 11!! We need to find you over 1000 RPM which is a little hard to swallow. I don't think she would plane empty if all of the info is correct. Seems almost like the gear ratio is wrong . . . Good luck!!!
