Re: force 70 H.P.
Make sure your throttle plates are opening in sync, and all the way. Check the condition of the new plugs after one hour, and look for a plug that looks new...None should. If you find one, run a compression test. You may have a blown head or exaust plate gasket, or the dreaded "holy piston syndrome".<br />I'd run a compression test regrdless, actually. Proper compression is vital to everything else. But the clean plug is an indication of water injestion.<br />Something else to check : Remove the prop and thrust bearing, and see if you fiond what appears to be a nylon washer. If you find one, discard it, inspect condition of lower unit lube by drain/refill, and try it. Fishing line can wrap around the prop enough to cause this, and besides making a perfect nylon washer out of itself (sometimes they look factory-made, but are just fishing line), they can also blow the propshaft seal, which allows water into the l/u, which can cause the symptoms you describe,just before the l/u grenades.<br />You could be not firing on one cylinder. Does it idle fine,without stalling when you put in in forward? If it stalls, or tries to when you place it into forward , it's often the only way to tell you are one cylinder down on a two-cycle motor.They most-times run fine in neutral,only to lack performance in gear.<br /><br />You might also have a waterlogged 'toon chamber on your boat. If it 'sits funny' in the water, i'd yank it out, and sound the pontoons for water.
