2000 90hp Low Speed Miss

[Bob Night]

Trbl.since engine was new. Whenever boat runs at low speed [ 900 to 1500 RPM] for about a 1/2 mile and I increse speed the engine develops a miss. After about 300 yards the engine clears out the miss. The engine runs fine all day until I slow down for about 1/2 mile again.Here is what I have done so far.Rebuilt carbs,fuel pump,replaced stator,coil,plugs, 3 bleeder hose check valves. Reajusted timing and carbs.The lowest bleederhose always has fuel in it.[ is this normal ?] :%

 

[Laddies]

Re: 2000 90hp Low Speed Miss

You need to have the system cked. with a DVA for low voltage at the stator and test the CDM modules

 

[Bob Night]

Re: 2000 90hp Low Speed Miss

You need to have the system cked. with a DVA for low voltage at the stator and test the CDM modules

 

[Bob Night]

Re: 2000 90hp Low Speed Miss

The stator is new and I bought a new CDM. I moved the CDM to each cyl. and the condition did not improve.This morning I removed the reed blocks and found some of the reeds were not flush with the blocks. They were not out past Mercs. specs. [0.020]. They were about 0.015. I will replace them anyway. :%

 

[Laddies]

Re: 2000 90hp Low Speed Miss

Bob reeds only effect idle preformance

 

[Laddies]

Re: 2000 90hp Low Speed Miss

If you have an induction tach hook it to a cyl at a time to see if you can tell which one is acting up, you might also ck and make sure the trigger voltage is 3+ volts when the problem accures but agian you will need a DVA to test it--Bob

 

[Bob Night]

Re: 2000 90hp Low Speed Miss

I think my #3 cyl has the problem. The spark plug is always weter than the others. I used a ajustable spark gap tool while cranking the engine and all cylinders had very good spark. But thats not in running under a load .

 

[JUSTINTIME]

Re: 2000 90hp Low Speed Miss

try it while opening the throttle at different positions

 

[Texasmark]

Re: 2000 90hp Low Speed Miss

Might try a decarb too. Won't take but a minute and cost is cheap. May be just the ticket if the above fails. Then you might want to try some different plugs as I just did. Performance did improve significantly; but not sure that will help your situation.....course if you weren't open for ideas, you wouldn't be on here asking. d

Go to Outboard Non repair and look at the post about OEM plugs originated by me...tweaked it just today. Silvertip has the info.

HTH

Mark