Mercury 84 & 82 90HP 2 stroke questions

[gflea]

I have an 84 90HP #6515252 with electric tilt & trim, but I believe it needs reed valves, as I've been through the troubleshooting guides numerous times. I found a good used 82 90HP #6026719 without electric tilt/trim, the replacement drive shaft and cowling part numbers are different. IE 7333A24 versus 7333T24. Will the tops interchange? And if I got lucky and found a 115 top would it fit the 90 bottom? Or should I just bite the bullet and find a newer 115HP, It's on a 1984 Lund Ty-ee. Thanks for any feedback.

 

[racerone]

How did you determine that the motor needs new reeds ?----The 2 motors are exactly the same parts I believe.

 

[gflea]

How did you determine that the motor needs new reeds ?----The 2 motors are exactly the same parts I believe.

Cylinder #5 doesn't fire correctly, removing spark plug wires. I've swapped coils, plugs & it doesn't change. The compression is only slightly lower in that cylinder. It starts easily, just won't run under load and smokes alot. I found some troubleshooting discussions and went through them a couple of times. I can't find a problem. But if you have any ideas that would be awesome.

 

[Chris1956]

Does the #5 spark plug look real clean? If so, you could have water intrusion, which is more likely than bad reeds.

 

[gflea]

Does the #5 spark plug look real clean? If so, you could have water intrusion, which is more likely than bad reeds.

Head problems? The discharge water when running on the muffs is loaded with oil, It ran good last year for 200 yards, then sputtered and quit. Now it will start, but it won't run on all cylinders

 

[Chris1956]

Check fuel pump diaphragm. If they leak, raw fuel is introduced into the crankcase, flooding a cylinder and into the exhaust, which shows up in the water.