Re: water on spark plugs 150 tower of power
That engine has no head gasket. The head is an integral cast part of the block. They are known for developing leaks of the water jacket cover that covers the piston tops and encircles the spark plugs which has no direct connection to the combustion chamber. No biggie just surface prep and a new gasket. I had to do mine in the 7 years I owned it (115 hp tower).
Water inside of all of them sounds like condensation or water in the fuel or something like that. If you had pin hole leaks caused by corrosion of the cylinder walls I doubt all would be wet simultaneously aka all having holes. Otherwise where did the water come from?
I ran a 115 tower at 6000 rpm with a Laser 19" prop on my "stock" 17 1/2' Ranger Fisherman with the pad hull at around 47-48 with a prop slip of about 12% for a reference. Per the Bam prop slip calculator you should be running 43 with that slip at your posted rpms assuming you have the 2:1 gearbox as I had.
Problem I see here is that for that many ponies, you should be running a lot more pitch and up in the high 50's or so.
Your compression must be good or you wouldn't be those rpms, however it's worth a check. My manual likes 120 for a low ball all within 15%. How's the carbon buildup on the cylinder crowns and plugs? If lots, maybe time for a "de-carb" (see archives) but that wouldn't be a water producer....performance yes, water no. Course 5500 is the top of your recommended rpm band at WOT so other than the water something doesn't make sense....instrument error, boat overloaded, trim incorrect for pad performance, dirty hull. Course trim and rpms are united; trim up (out) and rpms go up along with mph. Just a thought here: You are not trimmed properly, running the 19 on a 150. The engine is actually lugging at the 5500 with too much wetted area of the hull. The engine should be capable of running a much higher pitched prop on that boat and maintaining that 5500 rpm so if you got the trim right then the boat speed would increase as would the rpms and actually the engine would overrev. Water could be that you just started using the engine after storage for a while and it had condensation in it that just needed to be burned out.
So then you put on a 24P prop and run that engine on that boat at 5500, trimmed out properly, with about a 12% slip and now you are running 55 mph per Bam calculator, which is where I think you ought to be. I know the engine can do it as when I bought my boat new it was rigged with a 24 Laser and on the first outing I hit 55. If I can do it with 115 you can surely do it with 150. However, I realized the pitch was too much and I swapped props (less pitch) and was happy with the results. The lower pitched prop didn't strain the engine and gave me better control at slower speeds and especially in rough water conditions where I had to run much slower and the load on the engine much higher.
Best trim on my boat was out as far as it would go until the speed started to drop off. The Laser had all the bells and whistles and gave me great bow lift. At that high trim there was a pretty good rooster and I could hear two sounds: The engine singing at 6000 and the prop blades (3) beating the water making a drumming or humming sound. Neat!
Think about it.
Mark
