2003 Mercury 90 HP 4-Stroke Starting Problems

looneyes

Recruit
Joined
Aug 3, 2005
Messages
1
This is a carbuerated engine that is hard to start even using the fast idle lever. In most instances, there's no advantage of even using it. The fuel bulb is pumped and firm. Leaving the fast idle lever down and pumping the throttle lever and returning it to neutral will eventually start the engine after many efforts. As it fires, the throttle is immediately put into gear and the engine will idle quite roughly. Slowly accelerating, the engine will lose power and then gain speed around 1800-2100 RPM. Running this engine above 3100 RPM seems to respond normally. Slowing down to 1400-1600 RPM, the engine stalls and quits. Seldomly restarting without the full efforts as delineated previously. Fuel tank levels are maintained with fresh fuel with the correct measured addition of stabil as recommended by the dealer when new. Boat/motor headed to dealer for repair as still under warranty. I'd certainly appreciate any thoughts to be prepared for discussions with the dealer's technical people. Many Thanks!
 

Bigjohn1

Petty Officer 2nd Class
Joined
Jul 19, 2005
Messages
170
Re: 2003 Mercury 90 HP 4-Stroke Starting Problems

Sounds like you have done your part by keeping fresh stabilized fuel in her. I have seen this problem with the late model 90 4-strokes crop up on a few other boards. There doesn't seem to be any CONSISTENT diagnosis for this problem - here are a few of the diagnosis' I have read:<br />1. The carbs on this model are more prone to getting plugged up. Purportedly due to the carbs being soooo fuel efficient to meet the epa compliance.<br />2. A few people had a vacuum line which had fallen off. Re-attaching it fixed the problem.<br />3. One guy had a lever which links all the carbs togther fall off and they were out of synch. Re-attaching fixed the problem - according to him.<br /><br />The above are just a few ideas to ponder and perhaps check. Overall, this has been a VERY reliable engine it seems so I don't think your problem is widespread. Please give us an update when your dealer's diagnosis is complete.
 

Dunaruna

Admiral
Joined
May 2, 2003
Messages
6,027
Re: 2003 Mercury 90 HP 4-Stroke Starting Problems

Sounds to me like the choke is not working.
 
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