[ddaigle]

A friend of mine has 2002 150 yamaha with fuel injection. It tends to idle really low and sometimes dies before he can get it into gear. I thought the fuel inj. motors ran better than this? Otherwise it runs fine. This motor is way too complicated for my feeble mind. Are there any easy things we can check or adjust. I work on my own motors but they arent fuel injected. His boat is on a lift so its a problem to take to a mechanic. Any help is appreciated.

[rodbolt]

HELLO its a motor SUCK,SQUEEZE,BANG AND BLOW, all the high tech stuff does is make it more efficient.drain a sample from the vapor seperator. test the low pressure fuel pumps for leaking diaphrams. do you see a lot of gas spots in the water while it idles? have you cleaned the 02 sensor lately? how about changing the plugs? lots of basics on the motor that get overlooked. dont let the high tech intimidate you. it still has the basic fuel compression spark and exhaust cycles. the high tech on these motors rarely fails. usually if a high tech part fails the engine disentergrates or just wont run. good luck and keep posting

[ddaigle]

Thanks rodbolt, I know where the o2 sensor is on a car, but no idea on this motor. As I said its a friends boat and Ive never even had the cover off, he justtakes me fishing so I thought I would see if I could find some info to help him out. You have given me more than I hoped for.

[rodbolt]

ok buy a service manual or better yet get him to. it takes a 22mm sensor removal tool. the yammi one is not that expensive. the gastket kit is about 15 bucks. the o2 senor is under the black plastic cover up high on the stbd side of the block. you will need to remove the rear plastic cover as well as the lower stbd side electronics cover to disconnect the wires. the connectors are color coded.install new plugs. a quick test of the low pressure pumps is to pump the fuel primer and see if it will hold pressure in your hands or if it bleeds off. the TPS can be misadjusted as well. it takes a VOM and a 15 dollar test harness to check it. but if you check the idle timing and its correct odds are the TPS is right.idle timing should be 3*ATDC +- 2* good luck and keep posting