‘93 Intruder 150 Rough/Sneeze Idle and Won’t Reach Full RPMs

[ajmeyers4]

1993 Evinrude Intruder 150
E150GLETG
14.5x24p Raker
17’ Champion bass boat


Issues:
-starts right up but after quick start it idles rough / sneeze through upper exhaust relief. Doesn’t die, but it’s not running right.
-Holeshot and midrange up to 75% throttle is very strong/smooth. 80%-100% throttle doesn’t increase RPMs. Only getting like 4600 rpm WOT with hydro plate raised and trimmed out.


Not sure if these issues are related?


Lean idle makes me think that I have an air leak at carbs, throttle bodies, or VST. Maybe I didn’t set the float drops right? Is it reasonably possible that the CDI power pack is bad?


I can’t get this thing dialed in for the life of me. I’m open to suggestions. Thank you.


————————————————————————


The following has all been done by me or previous owner:


- Plugs
- CDI Powerpack
- CDI Optical Sensor
- CDI Plug Wires
- CDI Stator
-OEM coils
-Timing set at 6° ATDC idle and 20° BTDC WOT using timing light at cranking speed
-throttle & spark synced and opening at same time
-carbs cleaned and rebuilt (without white nylon washers)
-carb bowls sanded flat (no fuel leaks, primer stays hard)
-VST cleaned and resealed
-Double stacked fuel pump / VRO delete
-fuel tank cleaned
-lower unit resealed


Failed Troubleshooting:
-shift interrupt disconnected
-decarboned
-run on remote fuel tank
-squeezed primer bulb while running
-temporarily unplug rectifier
-idle timing adjustments


Next time I’m out I will
- verify idle timing
-ensure all cylinders are firing
-spray wd40 around possible air leaks
-put toothpicks in idle oriface
-spray pre mix down throats
- temp each cylinder with lazer. I’ve used fingers before and they are all too hot to touch more than a second or so.
-???

[ChampioNman]

Don't see any compression numbers and what plugs are you running?

[Simply_M]

Throttle body can leak around the shafts.

[ajmeyers4]

Sorry I should’ve included this info. Note that the compression test was done cold and I forgot to open throttle, so not ideal.

Compression:
95-103
95-105
95-110

Spark Plugs:
Champion QL78YC

[ChampioNman]

Look good.

[Simply_M]

24 pitch prop too much for a 150?

[Bassmeister]

I wouldn't think so on a 17 footer.

[ChampioNman]

24 pitch prop too much for a 150?

I ran a 24 Raker on a 20' Champion with a GT 150 and it ran fine right in the RPM range. Was a magical Raker.

[ajmeyers4]

Update on this:

Swapping stators and power packs did not improve performance(didn’t cost me anything). I swapped out the CDI timing sensor and now I’m finally able to feel power increase 75%-100% throttle. Not sure if the timing sensor was defective or un perceivably dirty. Idle seems to have cleared up a bit too. I did triple check timing and linkages are good.

Now I’m able to hit 55mph / 5000rpm with 2 guys and medium tackle load. Livewell empty. This is trimmed out and the hydro jackplate probably around 3” below pad. Rooster tail about cowling height. I know I should be shooting for 5600rpm and should at-least break 60mph.

Not sure if I’m over propped or not running right at WOT. I’ve tried two 14.5x24p rakers with very similar results. Plugs are a nice cardboard brown, but that’s after idling for a bit.

Not sure how to determine this outside of trying a different prop. Next time out I will take head temps. TIA

[ChampioNman]

Operating range for your motor is 4500-5500 with HP rated at 5000 RPM so you aren't too far off, maybe try a 22 Raker. How's the water pressure at WOT?