97 Johnson 150 Bogging off idle and 4k RPM MAX

[TuckNorris20]

1997 Johnson Fast Strike 150 J150GLEUC
1997 Stratos 282FS.
14 1/2 x 22 Rebel prop.
no jack plate
5” prop to pad height

I have the OMC manual for my motor. I have been following it to the best of my ability.

Boat is new to me. First thing I noticed was cracked and warped carb bowls. Replaced the bowls and rebuilt the carbs with OMC parts. Transferred the high speed jets. They are #69s. Replaced the port and starboard fuel manifold spaghetti gaskets also. Set idle mixture screws to 5 turns out. Still the bogging up to plane and 4k rpm max.

Found the motor had the wrong spark plug wires and NGK plugs. I bought a used set of OMC coils and wires and changed the plugs to the champion QL78YC.
Installed a new OMC power pack and a New CDI stator.
Bought JugHead316s easy timer and I am at 6 and 20 respectively.
Throttle roller has been replaced with a machined peice.
advance and throttle have been set to open at the same time. Throttle cables have been adjusted per the OMC manual.

learned about the VST and found the cover to be warped. Tried sanding it down and replacing the gasket, float needle and seat. Made it leak worse. Bought a used fuel bracket with VST cover. Installed the float,needle and seat in the new bracket per the manual, level with the house and I checked float drop. Within spec.

replaced the diaphragm in the vapor pump.

Rebuilt the VRO fuel side. Replaced all the fuel lines and the recirculating lines. Some OMC lines, others from Napa. If they were form fitted, I went with OMC as to not create any pinches in the lines.

Checked/cleaned fuel filter on motor and replaced the o ring and gasket.

fuel tank does not have anti siphon, and I’ve tried 2 different fuel bulbs, I extended the fuel line to orient the bulb in the vertical position.

AFTER ALL THAT I am still having bogging all through the rpm range and 4-4200 max rpm. Although it has recently started to do a sort of lean sneeze but it’s not the lean sneeze it’s what I call the rich sneeze. When it sneezes, it’s like someone is flipping a switch that turns on the power and it jumps forward. Once it does that a few times, it magically opens up and I can trim up and reach 5k RPM max. I just want this dang motor to run like a top. I enjoy mechanics but this thing is driving me crazy. Please advise.

[Bighare2]

Try pushing in the key switch when the bogging or sneezing occurs. If it runs better then you have confirmed a lean fuel condition.

[TuckNorris20]

So basically when I get it up to 4k rpm at 40mph and it doesn’t get any faster, push the key and see what it does. I will do that on the next trip.

[ChampioNman]

Almost sounds like the high speed orifices aren't installed or loose in the bowls, 4K is right about when the High Speed circuit kicks in. No CEL/horn? Bring the motor up to 3.5" below and see how it does.

[TuckNorris20]

No CEL and no horn. I have tested all the warning circuits per the manual. I put vacuum to the vacuum switch and at 7hg the check engine light comes on. I just did the carb rebuild a week ago and I made sure to transfer the jets over and seat them well. I can double check them though. I would love to bring the motor up but that means I need a jackplate. I was hoping to get this thing running well before I bought a manual jackplate. I’m going to try the key in at 4k and see if that changes anything. Then I was going to try backing out the idle mixture a full turn to 6 turns out. It doesn’t idle the best and my tach is showing 650-700 in gear on the water. Does moving the idle mixture out bring the idle up or do I have to move the tab on the top of the motor? I seen 316jughead said he likes to see these motors at 8-850 in gear on water. I’m not sure how to get the idle that high.

I have not looked into the reeds or checked the intake manifold gasket as of yet. Should I tear it apart and take a look at them? Or just go to the lake and try out the choke?

[ChampioNman]

The white nylon washers that come with the carb kits do not get installed during a rebuild they are used for the metal carbs, if you installed them they need to be removed throws of the float drop height. Were the bowls OEM or Amazon?

[TuckNorris20]

OEM bowls. Bought from leaders RPM. I did not install the nylon. I read where you said that on another post. Set floats level like the manual states

[basshackney]

98 Evinrude 200hp Vindicator

98 Ranger R93 Sport

Motor started bogging down and had to play with throttle to get on plane. Took to local shop and they replaced the stator which they said was bad. Got it back tested. Better but still bogs at take off and high rpms. Rebuilt carbs with OMC kits. Still bogging. Found the fuel pump had an issue and fixed it. Now no bogging at anytime but takes forever to get on plane and never gets above 4000rpms. Not sure I installed the white nylon washers. I remember seeing one white nylon washer per kit and I installed that one. Can someone send a pic or explain more in detail? Sorry for highjacking this post but this is so similar to my issue.

[poeman]

Yep that white one doesn't go. I made the mistake of installing it the first time also. Also check for spark on your plugs. I ended up needing a new ignition module/ power pack when mine wouldn't gain rpms and bogged down. A simple spark tester from harbor freight will help ya out about 5$ bucks

[ChampioNman]

The nylon washer is for the metal carbs and is not used in the plastic carbs. It is to isolate the dissimilar metals alloy/brass on the needle seats. Throws off the float drop heights if installed on the plastic bowls.

[TuckNorris20]

The nylon washer is for the metal carbs and is not used in the plastic carbs. It is to isolate the dissimilar metals alloy/brass on the needle seats. Throws off the float drop heights if installed on the plastic bowls.

ChampioNman -- I just received new thermostats and OMC primer bulb. I'm going to install those and take the boat to the lake, going to try pushing in the choke when it's bogging and when it is maxes out at 4k rpm. Going to bring idle mixture screws out to 6 turns and see if that makes a difference.
If I push the choke in and the motor speeds up past 4k what does that indicate...starving for fuel? Any other suggestions while I am at the lake?

[TuckNorris20]

So here’s my latest update after my lake run today.
Before I left I raised my motor to its highest setting which put my prop to pad at 3 7/8”. I installed new thermostats, and a new OMC primer bulb. It seems to hold its firmness much better than the attwood bulb.
I checked my timing pointer position. It does line up with the TDC mark perfectly following the manual with the piston stop.
the easy timer shows 6 idle and 20 wot. I checked the link and sync. Throttle roller and spark roller are set and everything opens at the same time.

I am still having the bogging off idle. It will “cough” or lurch forward with full power a few times and then it will open up and I can tell I have full power. You can definitely feel the difference in throttle response when it opens up. I actually achieved my highest rpm yet. 53-5400. 52mph. Yet, when it’s bogging/ maxed out around 4-4200 rpm/ 40mph or struggling to open up, if I push the key in, it makes the bog worse. I feel like this is an air leak issue or possibly something with the VST. I’m just so confused why I can’t get power whenever I want it. If I stop and fish for a bit and try to take off, the process begins again. Sometimes I’ll just have to let it bog out and then back off and trim up and then you will feel it want to go full power a few times and then I’ll just feel it open up. It’s the weirdest thing. I want to figure this out so bad. Could this be a bad float level in a carb or the VST? Reed Valve?

[TuckNorris20]

The nylon washer is for the metal carbs and is not used in the plastic carbs. It is to isolate the dissimilar metals alloy/brass on the needle seats. Throws off the float drop heights if installed on the plastic bowls.

Hey Champ,

I figured out my issue. On the top coil, I am arcing from the power pack connections to the spark plug boot. Now I need to figure out how to stop this. I quickly put some cloth between the spark plug boot and the primary connection. It came alive. But the spark was still making its way through occasionally. How can i fix this for good. This is a brand new power pack by the way. the arcing has already ate a hole in the primary wire boot.

[mactlman]

Hey Champ,

I figured out my issue. On the top coil, I am arcing from the power pack connections to the spark plug boot. Now I need to figure out how to stop this. I quickly put some cloth between the spark plug boot and the primary connection. It came alive. But the spark was still making its way through occasionally. How can i fix this for good. This is a brand new power pack by the way. the arcing has already ate a hole in the primary wire boot.

put some dielectric grease on the trouble spot might be carbon tracked or cracked. spark takes the path of least resistance so you might ohm out plug wires also

[ChampioNman]

Hey Champ,

I figured out my issue. On the top coil, I am arcing from the power pack connections to the spark plug boot. Now I need to figure out how to stop this. I quickly put some cloth between the spark plug boot and the primary connection. It came alive. But the spark was still making its way through occasionally. How can i fix this for good. This is a brand new power pack by the way. the arcing has already ate a hole in the primary wire boot.

Are the Orange high tension leads from the pack to coils shorting out or the spark plug wires from the coils to spark plugs? I've seen the plug wires arc to the block from wear and rubbing against the block. I'd replace all the plug wires with some quality plug wires CDI sells a set of 6 for $56.62 # 931-4921 on www.marineengine.com

[TuckNorris20]

[QUOTE=ChampioNman;13063661]Are the Orange high tension leads from the pack to coils shorting out or the spark plug wires from the coils to spark plugs? I've seen the plug wires arc to the block from wear and rubbing against the block. I'd replace all the plug wires with some quality plug wires CDI sells a set of 6 for $56.62 # 931-4921 on www.marineengine.com[/QUOTE

I found that one of the top boots has a crack in it on the underside. (right where it touches the high tension lead). It was arcing from the plug wire boot to the lead. I tried wrapping the top boots with electrical tape for now until I get the new set. It kind of worked. but the motor was still coughing. it must be making contact and then arcing or the spark isn't as strong as all the other cylinders. it bogs bad if I give it a hard throttle, I have to ease into it and then open it up. Ill get a new set of wires on there asap. My only concern after that is the tension lead boot has been ate away damn near to the cup, i just bought this dang OEM power pack. maybe epoxy or electrical tape the hole that was made? I need to figure out pictures on the forum so i can show you.