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1966 Johnson 9.5 SeaHorse problems

C

CMOS

Regular Contributor
Howdy All,

I recently found this motor in very nice shape. Had my local Automotive repair guy (who also does work on my mowers, chain saws, etc.) put in a Carb Kit but the darn thing just won't run or idle right. I understand that I just gave you very little information, but I'm hoping maybe for some "check this" or "adjust that" advice.

After I prime the fuel bulb it seems like the engine is flooded. Won't turn over for at least 20 pulls of the rope (choke on or off). When I finally get it to start the idle is awfully rough, and changes RMP higher and lower sort of randomly. When I try to throttle up in neutral I get an erratic and poor response and finally the engine dies. Repeat, same thing.

I plan to take the motor back to my mechanic this weekend but I'm hoping for some guidance first.

Thanks,
CMOS
 
Check your compression first. Then check your spark. It should jump a 1/4" OPEN AIR GAP on a spark tester. Don't bother using your spark plugs for this test as it's useless.
 
He did not check the coils but it appears that I'm getting a good spark, using the plugs themselves as a test bed. Do I need to get a "spark tester"? Auto Parts store?

Compression test was done before I handed over the cash. I got 120 from each cylinder.

CMOS
 
If you don't want to buy a spark tester ( around $8.00 in a parts house) stick a screw driver in the end of the plug wire and hold it 1/4'' away from the block and crank it.
 
kimcrwbr1, Yes, I did the compression test myself and got 120 on one cylinder and about 119 on the other.

I saw a very small leak in the Fuel Pump housing so I am going to do some work on that at the same time I do a proper spark test with tester. Question: what parts do I replace in the fuel pump? I do not see a "Fuel Pump Kit" for the year model that I have (MQ-12, 9.5HP, 1966). Help with this will be appreciated.

Next, you mentioned "running at the proper temperature". How do I assure this is the case? Should I just go ahead and replace the thermostat and gaskets as part of this effort?

Fuel; I mixed my fuel at 40:1. Any issue with this? I know the spec is for 50:1 but my thoughts are that I would prefer slightly richer than leaner when it comes to oil content. Thoughts?

Thanks,
CMOS
 
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50:1 is specified and is enough oil. 120psi is reasonable for that motor. In fact, very good. 18-7823 fuel pump kit should work. Make sure you have and follow the instructions exactly, they are a PITA in my opinion, but can be done. I think he meant "warmed up" before trying to adjust it.

One extremely common error on those is trying to run it in a barrel, especially with the hood on. Ain't going to happen.

Replace the thermostat if you want to. I have stock in the thermostat factory and need the money. Just kidding.
 
Not meaning to be a wise guy, but try sticking your nose down in there while it is running. Can't breathe, can you? Neither can the motor, since it sits down there in the barrel, inhaling all the smoke. With the hood on it doesn't have a chance of getting any fresh air.
 
A common problem with these motors is exhaust leakage under the cover. If the motor runs properly with the cover removed but will not run properly with the cover in place, you have an exhaust leak.
 
Guys, as part of this latest effort I am going to pull the flywheel to inspect the ignition parts. Will I need some type of wheel-puller to do this?

Thanks,
CMOS
 
A proper puller uses the 3 threaded holes ( 1/4-20 ) in the flywheel.------------So you say you do not see them.---------Remove the flywheel nut and the decorative stainless piece and there they are.
 
Mack, (IIRC you have an old motor similar to mine) the fuel lines look and feel brand new, and as I stated above I just had my local guy put in a complete carb kit. Let me get some of the above things done and I will report back. FYI - I opted to replace the entire fuel pump as getting the correct rebuild kit was sketchy at best. I'll work on my to-do list over the long Thanksgiving weekend.

CMOS

MackB52 said:
Carbonation sounds gummed up old fuel lines have to be replaced.needle jets cleaned..gaskets replaced good luck
Click to expand...
 
Update:

I pulled the flywheel. The ignition system parts are clean and look almost brand new. I checked the points gap, and they both were set correctly. I did clean the points contacts just for grins.

I also replaced the plugs (had not done that yet) and put in a brand new fuel pump. She seems to be purring like a kitten now! Good idle. Good throttle response.

The only issue that turned up is that I am unable to get the engine into the forward gear. Reverse works fine. I believe that when I replaced the impeller I may not have gotten the shift rod from the upper end all the way into the linkage connector. This could certainly prevent me from pulling that rod up high enough to engage the forward gear. I will put that on my plate for tomorrow.

CMOS
 
kimcr, can you expand on the below statements. I'm not sure I understand (although I may immediately when I loosen the lower unit and take a gander). I had a suspicion when I did the impeller that I may not have gotten the shift shaft all the way in the coupler. Guess I didn't.....


Oops. The starter rope just broke at the pull handle. What's the process to replace the rope???


kimcrwbr1 said:
The two bolts in the shift coupler need to be center of both shift shafts. I always clamp the coupler on the lower shaft nice and tight before installing the gearbox then as your spinning the prop pry up on the coupler push the shift handle to center the hole on the groove in the upper shaft.
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I just redid same motor , do yourself a favor buy a repair manual ebay has them if I didn't have that book I could of never done mine . I redid everything on that engine couldn't of done it with out book
 
So the small bolt will actually will sit IN the shaft groove when tightened, correct? As it is now, I can see the groove sitting under the coupler....

Also, regarding the external idle adjustment wheel - when I move that wheel I don't see any mechanisms moving at all anywhere under the cowling. This does not compute. Thoughts?


kimcrwbr1 said:
There are two shift shafts and the coupler the lower shaft groove needs to be center of the lower hole in the coupler and the upper shaft needs to be center in the coupler. You need to pull the bolt all the way out to get the shaft in the coupler far enough to center the groove in the hole on the coupler then install and tighten the bolt.
Click to expand...
 
It appears that I can shift into Forward now. I have a longer travel with the shift lever as I move it downward. I will know for sure after I replace the pull cord, start it, and load it in a barrel.

CMOS
 
That makes sense. Without turning the flywheel (or prop) it did seems that sometimes it was much easier than others to get it to engage in gear. I'll get my new pull rope this week and do a test this next weekend. Thanks for all the help thus far. I'm really excited to get this rig on the water.

Trailer is now fully painted. New bunks and lights/harness next weekend . . .

CMOS


racerone said:
Prop must be turning or flywheel must be turning when moving the shifter lever !!!!!!!
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The motor is shifting very nicely now. New pull cord is installed but I seem to now have an idle issue. The motor STARTS just fine but when when idling (after warmup) the idle sort of drops very quickly, motor bucks pretty hard, then the idle sort of recovers a bit then the bucking thing repeats.

Crud in the low speed idle jet?

CMOS
 
Pardon the ignorance but where is the slow needle and how do I adjust it?



kimcrwbr1 said:
Adjust the slow needle in gear on the water. Turn it out 1/8 turn at a time until it coughs and then back in slowly until it cuts out and back out until it idles smoothly. Wait about ten seconds between adjustments. Allways adjust it on the rich side for cold starts and a good hole shot.
Click to expand...
 
For my education - does adjusting this have a direct relationship with the idle in neutral?


kimcrwbr1 said:
Adjust the slow needle in gear on the water. Turn it out 1/8 turn at a time until it coughs and then back in slowly until it cuts out and back out until it idles smoothly. Wait about ten seconds between adjustments. Always adjust it on the rich side for cold starts and a good hole shot.
Click to expand...
 
The carb I have is slightly different than the one in your Ebay link. I have the type that has the flex cable coming from the low speed needle to a front panel adjustment knob (see post #18 for the LeeRoysramblings images of the 2 different types of carbs). I did play with this knob a little, and did get a better idle with it running more towards the rich side. I did not however, when adjusting, wait the 10 seconds between each tweak.

I'm at the point, probably, where I need to get it on the water so I can open it up and let it run, then see what adjustments need to be done, but that will have to wait bit until I finish the refurb on the boat. This next weekend I will try to create web page to host some pics of the project thus far.

Added question: I was trying to adjust the idle speed with the external knob on the tiller handle but I did not see any change in the RPM when I moved the knob. How many turns of the knob does this adjustment have?

CMOS
 
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Thought I would provide some closure to this thread, for the future benefit of others.

The motor is currently running like a scalded dog. The previously annoying rough idle and dies-at-idle was nothing more than too lean a mixture. Once I adjusted the Slow Speed needle it smoothed right out. In fact, I've learned that I'm better off adjusting the Slow Speed mixture during the day as I use it. A bit richer when I first fire her up, then lean out a bit once she gets hot.

As of yesterday, July 3rd, 2015 I have had the family out on the boat 6 times, and we're having a blast. I have gotten several comments about the "good lookin' old motor" from a few old timers who recognize it.

I'm also working on the next project: I found a 1982 Johnson 15 HP Long Shaft for $200. Needs some work but it has 120/120 compression and a good 1/2" spark jump on both coils. I just finished the conversion to short shaft today.

Thanks to all who helped with the 9.5. We're having a great time with this little motor.


CMOS
 
That's how I shut down now - disconnect the fuel line and let it starve on the boat ramp before I pull it out of the water.


CMOS
 
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