1972 Johnson 9.5 bogging down while in gear

[SAntrim]

Hey all, I'm about to rip my hair out over my outboard. In neutral, it will reach a high RPM, but in gear, it will only rev a bit past mid throttle. I've rebuilt the carb, checked compression on both cylinders which was around 62 on both and checked spark, which seems to be good. Just to make sure both cylinders were firing, while idling I pulled the plug wire off of one plug just to see if it made a difference, which was a drastic difference for both plugs (one at a time of course), so it seems that its running on both cylinders. Ive replaced the fuel pump, all new hoses and even a new fuel tank. I'm stuck....any suggestions??

 

[Crosbyman]

did you make certain the carb throttle arm was adjusted and very important did you make100% certain the HS jet was cleaned out these carbs must be 100% clean including all passages and chambers

comp islow but they work at those … see leroys
http://www.leeroysramblings.com/OMC_9.5.htm
https://www.youtube.com/watch?v=r-VTkOuSg00

 

[SAntrim]

Yes I checked the throttle. I removed the high speed jet and cleaned it with carb cleaner and then compressed air. Im at a loss....

 

[Crosbyman]

and did you do the chambers under the small cover plugs

is this a new problem

is this a new to you motor

see utube on chambers… and carb overall
https://www.youtube.com/watch?v=r-VTkOuSg00
https://www.youtube.com/watch?v=Y2pwU5aho9U

by the way did you overall the electricals… coils ok condensers, plug wires , points timing
test coil secondary 4-8 koms
http://www.pochefamily.org/outboard/Coils.htm
see video on timing
http://www.youtube.com/watch?v=ga1Cj...ature=youtu.be

https://www.youtube.com/watch?v=eNK2TEeQQv0&t=44s

 

[racerone]

Facts------Use a timing light to check spark on both leads as you throttle up in gear.-----Checked the reed valves ?-----I suspect it is only running on one cylinder at full throttle.-----Checked plug wires where they take a 90 degree bend coming out of magplate. ?----Does spark jump a gap of 5/16" on both leads , yes , no or not sure why that is an important test ?

 

[Crosbyman]

what happens in the bends…. both these wires were internally broken… in the bend stuff happens

 

[racerone]

Bring the motor over ---I find problem area real quick !!

 

[SAntrim]

The wires seem like there in good shape. My grandpa bought this motor brand new and its been in the family ever since. The initial problem about a year ago was it would not idle or run without choke. I rebuult the carb and then it ran perfectly for a few months. All the sudden, this issue started. I rebuilt the carb again and removed the cap plugs and cleaned the area and installed the new ones. I checked the timing and had to adjust both points just slightly, but still did not effect running at full throttle. Is it possible that it will run on both cylinders at idle but not full throttle?

 

[racerone]

Does it have a new set of ignition coils , yes , no or not sure ??----As stated ,---- with some simple proven testing it will be easy to figure out what is wrong !!!

 

[SAntrim]

The ignition coils have not been replaced since atleast 2004, which is when it was given to me.

 

[racerone]

I suggest you follow some of the simple ( no $$$ involved ) test procedures suggested.------These have been proven to get results over many years of repairing these simple motors / magnetos !!----Having had it in the family for all these years is reason enuff to fix it.----different than someone who got it at a yard sale for $25 or so.

 

[Tim Frank]

.....----Does spark jump a gap of 5/16" on both leads , yes , no or not sure why that is an important test ?

^^^^^

Step 1 !!
Cost = $ 0.

 

[SAntrim]

How do you test the spark gap?

 

[JohnnyGuy]

How do you test the spark gap?

Use an ignition spark tester like a "Lisle 50850".

 

[Tim Frank]

Adjustable open-air gap spark tester

 

[Crosbyman]

break the side electrode (ground) on a plug

ground the plug to the engine block and pull the starter ….does it at least snap and jump the gap ???

did you do some basic testing ...ex: measure resistance from the plug socket spring to the engine block with an ohmeter …

eliminate the easy stuff first and provide clear replies to questions …. by the way I know some don't like using SEAFOAM but it did wonders on my snowblower…. you can also try a good decarb product like Mercury Power Tune to clear some crud

did you service the carb properly like in the 2 videos … not just carb cleaner and air

 

[SAntrim]

I checked the spark today and I'm definitely not getting 5/16 spark. Ill probably go ahead and order new coils and wires tomorrow.

 

[Crosbyman]

NO … your are just throwing parts at an unknown issue …$$$$$

first pull the flywheel and look at he coils if not cracked they are likely OK

second at the very least try polishing up the points and adjust to .020 at the high point on the cam lobe (as a quick adjustment)
as a quick and VERY basic test of condensers get a cheap 15$ analog meter with a needle and measure ohms on the condensers the needle should kick down near zero and gradually increase back up ( use the high scale and adjust the meter to ) ohms before doing your testing)

as indicated… Measure the ohms on the coil secondary windings…. you should see 4-8kohms if you don't something is wrong and it may not be the coil at all... wires break, the spring inside the booth may not make good contact to the inner metallic wire... see picture

if you assume parts are bad you may spend more on parts than the motor is worth …!

 

[Crosbyman]

see page from the bible good book to read and learn from it does not cover a 9.5 but the magneto is pretty much the same concept wise read up on the CD AD FD section of ignition...

maybe cajuncook can send you his PDF … on the 9.5

https://bit.ly/2wqMPTb go see page 29 for basic…. timing adj. and points cleaning you already this some of this but did you clean the contact area with a bit of carb cleaner on a business card to remove any grease.