2005 BF 150 issues

I have a pair of 150's that idle rough the code they are showing is A/F sensor I checked the Ohms on sensor does not seem to be bad. I have run them hooked to a water hose and the water coming out of the pee hole stays cold could the problem be the thermostats not letting the motors get up to the right temp. Also while the motors were running I unhooked the A/F sensor and they ran a lot better.

Clean Idle air solenoid on front top of intake manifold. Thank's Martin

mcyama said:

Clean Idle air solenoid on front top of intake manifold. Thank's Martin

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I cleaned the IAC valve screens that did not help, that all seemed to be working fine.

Well, I would like to know how they run backed down at the river or lake. Most rough idleing unit's I see are high hour unit's that are carboned up and need a high dose of Sea Foam and Yamaha Ring Free. Once I know that valve face's and seat's are clean I will go ahead and reset valves to spec. But before that I will remove the inspection cover on the chain case and inspect the tensioner. If their is visiable wear on it, or you can move it back and fourth then it and the timing chain will have to be replaced. But this is only for high hour or unit's that have experienced a failure of some sort. Be certain that the quality of fuel in the boat is up to spec. Their are several other area's including injectors and exhaust corossion of the mount case that are common issues. Thank's Martin

I have ran Yamaha ring free through it and it has fresh gas. The motors have about 700 hrs on them. Do the A/F sensors or thermostats go bad very often ?

I haven't had any "BAD" A/F sensors on ZY6 model's however a wheel barrow load on ZY3 model's. Now the thermostates are a different story. It to could fill a wheel barrow. Don't forget that their are two different thermostates in your unit. Install the warmer of the two on the block side and the cooler on the head side. I sure hope your issue can rectified with a thermo. Thank's Martin

I have the thermostats ordered will take a few days to get, will let you know if it fixes the problem

I installed thermostats that did not fix the problem, one seems to run better but they still are not right. you can still unhook the A/F sensor and they run better. Not sure what to try next.

Why not replace the A/F sensor, that's what the computer is telling you ... :rolleyes:

I checked the Ohms on the sensor they seem to be good, where is the best place to buy them I looked on Iboats but I could not find them

What do you mean by checking the ohms on sensor?
Never trust ur ohms. It changes ..