Starting and Idle Issues

[bryanredfish]

Have a 2002 Mercury 90 hp that I like very much. Quick out of the hole, very easy on the gas, and not too noisy. One minor problem that I've noticed is that it occasionally dies at idle. In the water and warm, it idles at around 700 rpm's. In gear, it drops to about 650. The dealer, who is backed up 3 weeks right now, says it is probably just a low idle. He said that I could idle it up just a bit to see if that took care of the problem. He also said there could be something with the low idle adjustment (low idle jets? - forgive me, I'm new at this). Also, it's not the easiest thing to start, even when it's warm. Can someone suggest a quick fix since I have a fishing trip planned this weekend? The motor runs great once it's above 700 rpm's. Thanks much - lots of great guys on this board.

 

[orca]

Re: Starting and Idle Issues

These motors are real fussy to tune, 700 rpm is too slow, try lifting idle speed to 850 out of gear. you must adjust these motors in the water not on the muffs.

 

[bryanredfish]

Re: Starting and Idle Issues

I'll try it today. Thanks!

 

[jollymon]

Re: Starting and Idle Issues

Bryanredfish <br /><br />How many hours on the motor? Have you checked the plugs? How is your oil consumption?<br /><br /> I have the same motor and the same problems. Also mine runs real rough up to about 2100 rpms. When it had about 20 hours, it was so bad I took it back to the dealer, he "Adjusted it" and replaced the plugs. It now has about 45 hours and is doing the same thing. I looked at the plugs this weekend and they looked really dirty and oily. I also seem to go thru a lot of oil and smokes a lot. <br /><br />I spoke to my local Merc dealer and he suggested I replace the oil check valve to see if it helps the oil consumption and the smoking. ($8.95 and if it corrects the problem, he will refund the money and cover it under warrenty) It took about 3 minutes to change the valve. I also cleaned the plugs.<br /><br />It seemed to run much better this weekend, I hope this gives you some direction. Let me know how you make out.

 

[bryanredfish]

Re: Starting and Idle Issues

No particular Harbour:<br /><br />I have about 60 hours on the motor. The oil consumption seems to be normal, and I have very little smoking. I pulled the plugs, and they were not too fouled. Mine runs rough until it starts hitting on all 3 cylinders -- around 1200 rpm's. The issue seems to be with the idle adjustment. Were there any other symptoms with your oil check valve (leaking, etc.)? Thanks for the information!

 

[jollymon]

Re: Starting and Idle Issues

Bryanredfish <br /> <br />The first promblem I noticed, was hard starting, even when warm, (wachted my wife drift down stream, after engine stalled, while I was getting the trailer) stalling at idle, smoking rough idle.<br /> <br />All that and really still like the boat and motor.

 

[bryanredfish]

Re: Starting and Idle Issues

Sounds like the same problem I'm having. I've had a few interesting experiences trying to maneuver at the launch. Agreed, I love the motor, whent I'm above 1200 rpm's. Can you tell me exactly where the oil check valve is located, and if possible, details on how it is to be changed? Can a mechanically inept person do this? Thank you for your time.

 

[jollymon]

Re: Starting and Idle Issues

Bryanredfish <br /><br />It is easy to change, you need the valve and two wireties. <br /><br />I did mine while the boat was on a trailer. <br /><br />If you pull the cover off the motor, the valve is on the port side, towards the boat itself, it is about even with the bottom half of the cover. Cut the two wireties, making sure not to nick the fuel or oil line. The valve pulss out, then just pop the new one in, wire tie it and you done.<br /><br />The only thing that gave me a hard time, was where the fuel line comes into the motor, there is a gasket, there and I poped mine out, when I was trying to get my hands on the fuel line. It took longer to get that back in place then to change the valve. The whole job took less than 5 minutes.<br /><br />Good Luck