Re: 1991 V135 - Project Engine
Final status update - This project is complete now. I took the boat to the lake this afternoon and tuned it up on the ramp. I put the counter rotating prop on it and it didn't work. It didn't load the engine enough to tune it properly. I switched to a 14x19 Merc Silverado and that did the trick.
I drained the gas tank on the boat this morning and filled it back up with 52 ounces of Quicksilver Blend 2 Stroke oil and then 17 gals of gas. That should have given me close to a 40:1 mix which is where I think I wanted to be. It seems to have worked.
It took about 15 minutes of running for the smoke to start to clear up. The 20:1 Mix from the previous day did just like I think I wanted it to. It left a lot of oil behind.
Once the smoke cleared I rechecked the timing and adjusted the in gear idle to 750 rpm off the tach in my timing light. That's a little fast but o.k. for break-in I think. I then ran it up to 3000 rpm and checked max advance. It was at 19 which is also fine for break in.
I then launched it and took it for a spin. I ran it at 1800 rpm for 15 minutes then took it up to 2500 for 5 minutes. I repeated that for close to two hours. Man was I getting anxious to just stuff it.
If your wondering why 1800 rpm, it's because that just happened to be a sweet spot I found where everything sounded really good. I think the poppet valve opened around then too because water pressure dropped a little and engine temp came up to 145. That's as hot as it ever got all day.
At 4:00 pm, just as the sun was hiding itself behind the mountains, the breeze died off and the lake turned to glass. Hammer Time!!!!!! I took it right up to 5000 rpm and she sounded soooooo sweet.. I think I saw 44 on the GPS and still had throttle left but I regained control of myself and slid it back down to 3000 and cruised it back home.
It's a little early to tell for sure but she feels like she'd be better fitted with a 17 or a 19 with a little less cup than the Silverado. I haven't found the right height and trim combo yet but with the hydraulic jack plate it's just a matter of playing with it. The 19 might be the right prop when it's all set up. We'll see.. This is a 25" shaft on a boat designed for a 20. The jack plate has a 5" offset and up to 7" of lift. The engine set so with the jack plate all the way down the cav plate on the engine is just 1" below the bottom of the boat. I ran it 3 inches above the bottom (4" lift) today and I powered it through tight turns without any venting at all. I could probably go another inch up without any problem but I think I'd need to change to a prop that's designed to work near the surface for it to make a real difference in performance. A guy could go broke buying props.
So.... here's my new dilema... It's only flippin Nov 1st and my winter project is done. Currraaap, what now!
