I am trying to diagnose a motor for someone. He just bought the boat/motor. The motor is a Suzuki Dt60 about a 1984. It is oil injected, 2 cylinder,2 carburetors. It is a very low hour motor, very clean under the cover. We took it out when he bought it a week ago and it ran great. We had it out approximately 45 minutes and idled and cruised/accelerated without a flaw. It pumped water great. Compression on the motor reads about 140 on both cylinders. Fuel filter was checked(clean), tank is clean, newer hose and primer.
He took it out again and this is what it did. It started at the dock and idled out of the harbor fine. There is a long no wake zone so you have to idle for aways, it ran fine the whole length there. Upon acceleration it it took off fine and ran fine top end for maybe ten minutes then the rpms began dropping down on its own without moving the throttle- nearly down to a fast idle. He limped back with it and I took it out today and verified the problem. I got down the channel to the end of the no wake zone without a problem running at a fast idle (slow speed). I put the throttle down and the rpms increased normally and the the boat got up to speed. I ran for a minute like this, and then pulled back on the throttle down towards a fast idle. Upon trying to reaccelerate, the motor just bogs and will not accelerate. It makes a slight popping noise out of the exhaust when doing this. I limped back to the dock and pulled the spark plugs, and to my surprise they seemed realatively wet. I checked for spark and it seemed to have it on both cylinders. I put in a dry set of plugs and tried it again. I was able to accelerate normally again, but after about 5-10 seconds of running wide open, the rpms began dropping again. Again I limped back and pulled the plugs. They seemed pretty wet again. Also while I was running it and it would not increase rpms, I tried squeezing the primer bulb-I was told if the fuel pump is weak, this would make the motor increase rpms, but it didn't seem to help. I also blipped the choke while it was doing this and it seemed to briefly increase the rpms alittle.
Does this sound like a fuel problem or an electrical problem? It seemed like the oil injection was working because the oil level has gone down some, and the plugs don't look the the motor was running hot, although is there a limiter that will decrease the rpms on this motor if it is not getting proper oil amount?
I figured if it was the fuel pump, the plugs wouldn't seem so wet. I would say maybe the carbs have gunk in them, but then why does it run good initially? Would a bad stator or coil. etc. act like this??
Your help would be greatly appreciated. The nearest Suzuki dealer won't work on it, they only work on the 4 strokes. If I can get a consensus from a few of you, maybe we can get this going strong again with few parts.
He took it out again and this is what it did. It started at the dock and idled out of the harbor fine. There is a long no wake zone so you have to idle for aways, it ran fine the whole length there. Upon acceleration it it took off fine and ran fine top end for maybe ten minutes then the rpms began dropping down on its own without moving the throttle- nearly down to a fast idle. He limped back with it and I took it out today and verified the problem. I got down the channel to the end of the no wake zone without a problem running at a fast idle (slow speed). I put the throttle down and the rpms increased normally and the the boat got up to speed. I ran for a minute like this, and then pulled back on the throttle down towards a fast idle. Upon trying to reaccelerate, the motor just bogs and will not accelerate. It makes a slight popping noise out of the exhaust when doing this. I limped back to the dock and pulled the spark plugs, and to my surprise they seemed realatively wet. I checked for spark and it seemed to have it on both cylinders. I put in a dry set of plugs and tried it again. I was able to accelerate normally again, but after about 5-10 seconds of running wide open, the rpms began dropping again. Again I limped back and pulled the plugs. They seemed pretty wet again. Also while I was running it and it would not increase rpms, I tried squeezing the primer bulb-I was told if the fuel pump is weak, this would make the motor increase rpms, but it didn't seem to help. I also blipped the choke while it was doing this and it seemed to briefly increase the rpms alittle.
Does this sound like a fuel problem or an electrical problem? It seemed like the oil injection was working because the oil level has gone down some, and the plugs don't look the the motor was running hot, although is there a limiter that will decrease the rpms on this motor if it is not getting proper oil amount?
I figured if it was the fuel pump, the plugs wouldn't seem so wet. I would say maybe the carbs have gunk in them, but then why does it run good initially? Would a bad stator or coil. etc. act like this??
Your help would be greatly appreciated. The nearest Suzuki dealer won't work on it, they only work on the 4 strokes. If I can get a consensus from a few of you, maybe we can get this going strong again with few parts.