95 9.9 weird idle issues

[just_james]

Just took boat out to do final adjustments and for some reason idle seems erratic. Here's the history behind this motor. Got it in 14 and did normal maintenance since history wasn't known. Did run for summer. Then I parked it till this year. This year I put new Seastar remote on it and cables adjustments per OWN manual. Carb rebuilt down to removing welch plug from carb body to clean idle circuit. Fuel pump rebuilt and complete water pump assembly installed. Did a decarb running Sea Foam thru carb the let sit over night. Compress on top cylinder is 95 dry,108 wet with oil,
lower is 97 dry, 110 wet. Top cylinder spark will jump 1/4-5/16 gap , bottom jumps 1/2". I did notice that idle in gear seems like vacuum for fuel pump isn't pulling enough fuel. If I pull plug wires off one at time engine stumbles.

 

[just_james]

bump

 

[Joe Reeves]

You've pretty well covered the bases pertaining to what you've done to the engine... BUT... other than stating that "the engine stumbles if you remove a plug wire" (which is understandable), you haven't stated exactly what the engine is doing or not doing. We need a explanation of the engine's problem(s). Explain your "weird idle issue" statement.

The compression is okay... the spark should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! (Not a thin weak line). You state 1/2" bottom and 1/4 to 5/16" top.

If 5/16" spark is all you can get out of the top coil, that won't do! Check all wires, terminals, etc for continuity, switch coils (if individual coils) to see if the weak spark problem follows the coil.

 

[just_james]

Joe, what is happening with the idle is that it fluctuates up and down when in neutral. Sometimes it will stall when going into gear. Once I restart, I can get it in gear but it will bog down until I hit about a 1/4 throttle.

I did pickup a new primer bulb this morning. I noticed last night that there was a little fuel coming out the inlet end of bulb.

As far as spark on top cylinder my coils are not individual. I'll have to check the wiring like you say to day. I do have the OEM manual. One other thing I need to do it check upper cylinder spark with timing light to see if I'm losing it, but right now I have no one to drive while I'm hanging over the nack.

 

[oldboat1]

would be a dual coil unit (about $40 to replace). Wouldn't hurt to check and clean the connectors in the boots. Make sure the primer bulb has the arrow in the direction of the engine, and that the tank is vented. Try loosening the cap. Might pump the primer bulb when having problems (see if the fuel pump is an issue). The carb has an idle adjustment needle -- may need adjustment.

 

[Joe Reeves]

Joe, what is happening with the idle is that it fluctuates up and down when in neutral.... As far as spark on top cylinder my coils are not individual.

Having a engine fluctuate up and down is usually a two carburetor problem (or three)... however I have also run into that problem with 9.9's and 15's and always found that it was due to having the slow speed adjustable needle valve set slightly too lean. Does that 1995 model have an adjustable slow speed needle valve or a fixed jet. If a jet, is the jet a air bleed or a fuel flow jet?.... if air bleed, a smaller ID would cause more fuel to flow... if a fuel flow jet, a larger ID would be needed for a richer mixture.... if that is the problem.

The one unit dual coil component.... to test the coil, simply switch the wires from the powerpack that leads to the coil assembly. If on a spark test, it is still the top coil that is weak, then yes... that top coil section is faulty.

If however (with the powerpack leads switched), it is the bottom coil now that is weak... that indicates a powerpack problem.

 

[just_james]

Well I got around to swapping coil wires around and the problem traveled with wire. I did however received my DVA adapter today so I will fool around with it this weekend.

 

[thatone123]

I have probably dealt with at least 30 of these outboards and seldom see spark issues, but that does not mean it won't happen. Some of the carbs just don't seem to want to come clean. Clean with spray carb cleaned then Soak in Berryman Chem-Dip or similar for 24 hr. Swishing the can from time to time. Then put in hydro-sonic machine. (available on Amazon for under 100 bucks) Then clean with carb cleaner again (I don't recommend using water like some say.) and then use compressed air to blow out passages. You can take out welsh plugs or not, up to you. This is all possible on the 74 up to a certain year, 80's which I am most familiar with as the main carb body has no plastic, not sure about some of the late model carbs. As the harsh Berryman may destroy plastic they say, although I have never seen that happen. I have a few 9.9 carbs that were switched out for the 15 carbs and I have given up on them as they don't want to come clean. Hope this helps!