silverado636
Cadet
- Joined
- Jun 5, 2005
- Messages
- 6
1968 33hp Johnson. The engine will not open up to full throttle. It will only idle. Last summer I replaced the plugs because it is something I do every year. After I put the new plugs in the engine would not rev up. I put the old plugs back in and same problem, only this time I stripped the bottom plug threads. I pulled the cyl head to install a heli-coil. I discovered badly worn pistons and decided to install .040 oversize pistons and have the block bored. When I started the engine after the overhaul it fired right up and idled fine after a slight low speed carb adjustment. I test ran the engine for an hour revving the engine in gear to try WOT. It revved flat out. I ran it at different RPM to break in the pistons?? When I put the boat in the water this weekend it would only rev a little above idle. All the linkage is moving freely and not binding. If I manually open the throttle plate and advance the timing by pulling on the linkage the engine will rev up. It seems under load it will not rev up. The carb has had a kit installed. <br /> Why will the engine not open up??