Re: T2Stroke

[Don]

It is probably easiest to just unplug the safety lanyard/kill switch from the dashboard/control box, this will kill the spark while cranking.
Needless to say, having the fuel supply nearby and in the cylinders makes cranking the engine with the plugs out dangerous. I suppose it is best to leave all the plugs in (except for the cylinder with that gage in it) while cranking, even though the cranking speed might be low, so charge up the battery beforehand. The problem here is that the cylinders are full of oil from winterizing, so the compression readings may not be accurate.

OK, so the boat is relatively new to you, and has never run correctly since you bought it, correct? I’m guessing the engine ran like this for the previous owner, he just wrote it off as needing a "tune up". Perhaps he messed with something causing the lean spit, but I guess we will never know… The whole altitude thing is a bit of a grey area, anyway of trying the rig at lower altitudes without driving for hours? Nonetheless, conventional altitude kits usually include leaner jets for higher altitude, which will only make the "sneezing" worse. An engine that sneezes at idle usually does this because it is lean. But, an ignition problem/timing issue could certainly cause the engine to lean spit also. Once again, your engine has idle air bleeds that help control idle fuel/air mix, this is another confusing issue…Putting in smaller air bleeds richens the idle mixture, which is what Dan was trying to accomplish by blocking the air bleeds off with toothpicks.

The oil injection system on this engine has been disabled, which is fine…But, how was it disabled? Is the original VRO/fuel/oil pump still in place? Keep in mind that there are two crankcase ports that supply crankcase pressure/vacuum pulses to the conventional fuel pumps, the VRO only uses one of these ports. One of the ports should be blocked off on your engine, don’t know if it is blocked with a conventional threaded plug, or just a rubber boot. A leak on one of these ports will definitely cause a lean condition/spitting. A problem with the VRO’s air motor will create a leak/lean spit, BUT that would usually mean the unit would not pump fuel so the engine would not be running, much less at high speeds. An external crankcase leak is usually easy to spot, but your crankcase is painted black, so it is not that easy. Dan mentioned that the engine will drool fuel/oil residue out of the front cover normally if the gasket/cover/bolts are not properly installed, but does it seem like there is excess fuel/oil drool on any other part of the engine? Dan also mentioned the recirculation system, perhaps one of these hoses is off the fittings/split causing an external leak.

But, I am getting a little ahead of myself here. We definitely want to check the synchronization on this engine, overlooking this will only confuse and perhaps create other problems. There are two components to synchronization, the carburetors and the ignition system. So, for now, try to take some pictures of the engine, close ups on both sides of the carburetors. I need one important picture…With the control box at dead idle, take a picture on the right side of the engine showing the throttle cam/roller and carb linkage….

Finally, you mention the engine has a 17" pitch prop, and turns up about 5000RPM, which seems normal for the base 150hp, so it would appear as thought it is developing full power. It would appear that the 1989 base 150hp does not use the quikstart feature, but we need to verify this…There is a termperature switch/sensor located near the top of each cylinder head, try to locate them. If the engine has quikstart, one temp switch will have two leads coming out of the head, one will be white the other will be tan. Non quikstart engines have a single tan lead coming out of each temp switch on top of the heads.