merc 90 restarting

[matty133]

My 84 merc 90 inline 6 runs great. It usually starts well out of the water but sometimes i have trouble when i put it in the water. I have to choke it while turning the key and throw it in gear to get it going. This is both in and out of the water. When ive been boating for awhile and then shut the motor off for more than 15 mins it is nearly impossible to start. The same technique doesnt work. I have to reprime, choke, and then crank it for a long long time. I carry a second battery because it will drain the battery so bad. What do u think the problem is? Also the battery doesnt charge at all. I can get about 8 hrs out of a battery before it needs a charge. Any help would be great

 

[fishingdan]

Re: merc 90 restarting

Have the carbs ever been rebuilt? If not, it is time.

 

[timmathis]

Re: merc 90 restarting

Really need to do a carb job. If it has not already been done. Check the timing and make sure plugs are good.<br />You could try some seafoam to help clean out fuel supply. Make sure motor is all way down when starting also after firm give the bulb 2 or 3 extra hard pumps before starting. Tim

 

[jaybirdtx]

Re: merc 90 restarting

To me it sounds like the stator, rectifier, or voltage regulator have some issues. A simple check for the regulator is use a voltmeter @ the battery terminals and check for 12-14 Volts DC as the engine is reved up. If it doesn't hit 14 VDC chances are the stator or rectifier have took a dump. To check the stator, disconnect the 2 yellow wires @ the rectifier. With the engine running, check for 14 Volts AC. No voltage=bad stator. Reconnect the yellow wires and disconnect the red and black, check for 12-18 Volts DC @ the rectifier terminals. No voltage=bad rectifier. If all of these check good the problem will be in the ign. pack.

 

[Bob H.]

Re: merc 90 restarting

It's sounds like you're not using the fast idle lever correctly, if at all when starting. The carbs need some attention if it's hard to start after running, it sounds like they're flooding. When you turn off the ignition, open the throttle for a while to evaporate any fuel. Close the throttle when starting and see if behaves. There also seems to be some charging issues. You need to check voltage when running as OBM stated above.