91 Yamaha 200 stalls at idle speed

Hello, My 1991 Yamaha 200 Saltwater Series II just had a new water pump and thermostats installed. The next time I used it, it ran great...until I approached the fuel dock. It immediatley stalled when brought to dead ahead speed, and was very difficult to restart and keep running when shifting. It continues to have this problem. I don't beleive the mechanic would have had any reason to change the idle speed, so I am thinking it is something more? Any ideas? Thanks.

Re: 91 Yamaha 200 stalls at idle speed

sounds like water or trash in the fuel system. have a look at the engine mounted filter. and run a compression test.<br /> good luck and keep posting

Re: 91 Yamaha 200 stalls at idle speed

Thank you for your feedback. I agree it does sound like a possible fuel filter problem, and I will check it. But, this problem occured while on an extended trip, and I had been running it for days with no problems, on the same tank of fuel. It also runs fine once the RPMs are high enough. Nothing had changed except it being in for service, and the lower unit being removed to replace the water pump. (I think?) Should I try adjusting the idle speed? I know the adjustment is made on the carb, but do you happen to know the location of the adjustment screw? I am a novice at this, but understand engine systems. I have also heard that there is a retainer clip or something on the lower unit gasket? that, if left off after serviceing, allows water to enter part of the engine that causes it to stall at low idle. Not sure if this is from a reputable source. <br />Also: How do I perform a compression test? Thanks again.

Re: 91 Yamaha 200 stalls at idle speed

do not adjust anything. its broke<br /> time to fix it. test the fuel pumps for leakage by pumping the primer buld and see if it stays hard or not. the motor is trying to tell you its sick. if you dont cure it it will die. trust me on that. it is a very precise high perfomance machine. all the subsystems must work correctly or it eats pistons.go to walmart and buy a compression tester. then remove all the plugs and the engine stop lanyard. then test the compression. if it has good compression odds are something is in a carb or one of the fuel pump diaphrams is torn. the latter never happens with maint .<br />a leaking fuel pump can waste a piston on that motor. its time to buy a service manual and read and understand it or take it to a tech that can troubleshoot.<br /> there is nothing with the water pump that will cause a poor idle unless the previous pump had failed and you overheated it. it only takes one overheat to kill a motor.<br /> good luck and keep posting

Re: 91 Yamaha 200 stalls at idle speed

Hmm, I did overheat it. The overheat alarm went off and I shut it down. I could not get it to cool off, so I did not restart it. I had to get towed in and I had them replace the water pump, thermostats, etc. <br />I will buy a compression tester, and have a manual en route to me now, just wanted to try to get a headstart.<br />I just bought the engine, and was told it had been maintained. I guess I'll find out. Thanks for the info.