How to sanity check link and sync? Johnson 110 lack of throttle response and stall.

Hi,

The Johnson 110 I've been monkeying around with finally made it into the water. It's pushing a 17 foot aluminum boat (hardly a load)..

Compression by my gauge is 95 a cylinder +/- like 1 psi, but I don't really think my gauge is right and suspect it's probably a little higher.

Starts right up and runs OK, will rev up to whatever with the warm up lever, however upon putting it in the water it was like I had 30 HP. Runs fine in gear up to 2000 RPM then if you push the throttle any further either it stalls or just doesn't do anything. Primer bulb, primer solenoid, playing around by trimming the engine up doesn't do anything - might get 2200 RPM or something. Can't even get it to jump up for an instance - would not call it a bog rather it's like there is no response to the throttle.

Carbs just rebuilt. New plugs.

What I noticed upon setting the idle was the screw was practically maxed out. Also seems like there is barely any travel to the trigger and that at full throttle it's at like the center of the entire range you could set it to. The adjustment on the trigger (by the threads on the linkage) is very far in the direction of retarding the timing.

Carbs do open fully upon contact with the throttle stop, however my suspicion is someone mucked with the timing at some point and it's somehow waaay off.

Since I couldn't even get this engine to 5000 RPM if I wanted to, how do I verify that the WOT timing setting is sane? Do I seem on the right track with this or should I go back and verify carbs first?

Thanks!

Jon

Does spark jump a gap of 7/16" on all 4 leads ?--------------Orange / blue go to the top coils on both sides ?

racerone said:

Does spark jump a gap of 7/16" on all 4 leads ?--------------Orange / blue go to the top coils on both sides ?

Click to expand...

Will check that wiring and measure the spark tomorrow, also got a new timing light to try out.

Thanks!

Jon

I checked those wires and they are on top - the spark jumps at least 7/16, I think I checked it closer to 1/2 inch.

Without any good idea of how to check the timing, since the linkage setup looks funny to me, I checked WOT using the starter and plugs out, it was like 12 degrees. I don't know what sort of difference that makes with the engine turning on the starter versus at 5000 RPM but as a trouble-shooting step I set the advance to 25 degrees using this method and re-tested.

I just backed the boat down the ramp and spun the prop on the trailer. It's still doing something like a 2000 RPM thing but the stall seems to be mostly gone, and obviously there is no opportunity for the engine to actually pickup any speed...

Since it's got a 21 pitch on there now (as I thought it would want that given the really light load), going to try a 19 pitch prop and see what difference that makes.

Outside of that my only other idea is to tear into the carbs again but not sure what to be looking for. I did mess with the floats a lot when putting the carbs together, any chance a float setting would allow it to run well at idle but never get going?

Jon

Where the high speed jets removed from the carburetor bowls for inspection and cleaning ?-----Have you checked the flywheel key ?

racerone said:

Where the high speed jets removed from the carburetor bowls for inspection and cleaning ?-----Have you checked the flywheel key ?

Click to expand...

The carbs were taken apart pretty well (everything other than the butterfly parts); I forget where those jets were but remember taking out 2 sets. Everything got cleaned good, but there is always potential for error. The flywheel key I will check but I did find TDC to be lining up with the TDC mark on the flywheel, I put that on about a month ago and remember doing it carefully, also was carefully torqued.

So here's what happened when I went down to the 19 inch prop. At the ramp I feel like it's still lugging when I just pin the throttle open, I expect it to rumble and cavitate up to 3000-4000 RPM and what it does is runs OK but can't seem to find the power to get above 2500. It just runs like that sounding like a 4-stroke with the RPM low and butterflies wide open. I still figured it was worth a test run.

During the test run this is what it did - jam the throttle wide open and it does one of 3 things. #1 (most commonly) hits like 2200 RPM and just kinda lugs.. #2 if you start playing with the trim and coax it into getting going by allowing it to cavitate some, at just the right spot instantly the RPM jumps up to 5000 and the boat takes off like a bat out of hell.. #3 the cavitation of playing with the trim doesn't stop and you need to start over..

It's like you need to coax it into the powerband while also making sure the prop gets enough traction, then it goes.

It basically is completely lacking the mid range to plane a 17 foot aluminum hull. Once you get it over 2500 RPM it screams up to 4000+, but can seem to get there turning a prop that is getting good traction. Does this ring a bell as far as where to look?

Thanks!

Jon

Are all cylinders firing when it is bogging; check it with a timing light while on the lake. Good luck
r

Will Bark said:

Are all cylinders firing when it is bogging; check it with a timing light while on the lake. Good luck
r

Click to expand...

Thanks - I will add that to the plan of what to do next. I think the way to trouble-shoot this is going to be stick with the 19 inch prop and use that as a test wheel with the boat on the trailer. I really think when the thing is good it should be acting powerful even when on the trailer instead of dogging under 2500 - will be easy to add a light to the setup.

Also am thinking I'll at least re-check the timing in gear at whatever RPM I can get it up to. If the test on the starter was anything near correct it was off by at least 14 degrees. I think I did fix something there because before it was hard to keep it running at full throttle, now running is not an issue it's just not as powerful as it should be.

When I first got this engine it was death by carbon - I attributed it to a rouge VRO, which seemed to be pumping oil at like a 1 to 1 ratio. It's possible the primary issue was actually having the timing so far behind.

Now the primary carb pickup is no longer quite right, so I should go back through all that, however still I'd expect at full throttle (given both the throttle and timing should be correct) the engine would be making full power.

Jon

You have to be really carefull when you adjust maximum advance timing on one of these motors.------Reason being that timing is fixed at the factory for the life of the motor.------Bad things happen when timing is wrong.

racerone said:

You have to be really carefull when you adjust maximum advance timing on one of these motors.------Reason being that timing is fixed at the factory for the life of the motor.------Bad things happen when timing is wrong.

Click to expand...

Ya I didn't really want to mess with it but looking at the idle adjustment screw, basically maxed out to hold 700 RPM in gear, seems like something must be wrong. The fact that the locking nut easily came loose and the thumb screw moved as easily as it did leads me to believe it definitely got messed with before.

When I checked the idle it was about 5 degrees, which seemed OK to me with the exception of the idle screw shouldn't be maxed out to achieve 5 degrees.

Once I get some bearing on how to really make it run right I will need to go and carefully get everything set. Every book I've ever had detailed a process of adjusting the link, sync, and max advance when performing a tune-up. Typically nobody messes with the last part of max timing?

Thanks,

Jon

OK - here's where I'm at now.. Haven't yet fired it up but learned some things.

Ran across a fellow that worked on many of these in there era, first question he had was "plastic carb bowls?".. "Yah they warp and cause an air leak that does that"..

I knew there was something suspicious with the bowls, noticed they were a little warped and had issues with leakage out (basically the internal inlet was allowing fuel to pass by the float) - had tinkered around and got them not leaking so much out but never considered the fact it could also cause an air leak during suction. I found one new bowl on ebay and re-surfaced the other to eliminate the .019 gap between the securing screws..

Re-inspected all jets for size and cleanliness - no issue there but trying to prevent fuel leaks I had the floats set very wrong. In the process of rebuilding again I set them to the book.

During re-installation of the carbs I noticed down on the lower port side I left an intake manifold bolt sticking out like 1/2-inch.. Big time DURR. All others not only got tightened but got torqued. Somehow I just didn't see that one, don't get how I missed that but obviously a bad thing..

Pulling plugs to re-check TDC I found now that I ran the engine a little the port side lower plug is also very clean compared to others (which are what you'd expect running not quite right at 25:1). Gotta assume it's related to the port side intake bolt sticking out, if not it still has to mean something - hopefully I didn't manage to score a cylinder running lean already (could also be water leak or spark issue I guess too).

Fuel in boat has no water but doesn't strike me as being very good upon second inspection. Smells funny, is brown - maybe from additives but I dunno - on the test run it's getting new fuel in my 6 gallon tank, everything has been flushed out.

Found a missing a bushing in the linkage - was creating so much slop it threw the timing advance way off. Replaced.

Seems like somewhere in here I should make progress (even if nothing is related other than the one clean plug). Test run soon after I go through lynk/sync again.

Thanks!

Jon

A like new clean plug usually means no spark or no fuel.

racerone said:

A like new clean plug usually means no spark or no fuel.

Click to expand...

Ya I'm really hoping it's no spark because getting no fuel is not exactly a good break in procedure... but the sort of vacuum leak I may have created with that intake manifold bolt how it was I gotta think it's probably lack of fuel.

It does also appear to have spark the same as the others but there are some things I need to go and do once it's running again. Got a bunch of recommendations on how to go cylinder by cylinder with it running to verify consistent spark.

Thanks!

Jon

Checked compression on that clean plug, fearing the worst - same 95 psi as the others. Got it put back together and did an initial quick link/sync, retarding timing back to where it was. Started up a little shaky, some tuning of the idle and it sounded OK. I noted a prominent snap with the warm up lever I had not heard before..

Checked that clean spark plug and indeed it now was beginning to look a little oily. In the process of getting ready to head to the ramp for some more testing noticed upon installing the cowel the idle dropped. Adjusted it a little higher and headed to the ramp.

At the ramp I found with the cowel off the thing revs right up, blows the prop out on the trailer, big difference. 4 degrees advance was like 1200 RPM (before that was like 7)..

Upon re-installing the cowel I found intermittently it has a bog. I searched and searched for an exhaust leak to no avail.. I poked and prodded the wires with no change in behavior - even went cylinder by cylinder with the test light and the cowel installed - somehow could not reproduce the problem with the test light hooked up. However simply lifting the front of the cowel up 1/2 inch was like a switch if the problem was noted, up and it ran good, down and the RPM dropped.

Back at home with a flashlight I found that spark plug that came up clean before has a puncture in the boot on the coil, which directly lines up with a bolt on the clamps that secure the cowel. Will correct that and test again but I think I'm having multiple problems and am getting real close to the bottom of it all.

Jon

I had a similar problem as yours, the engine (1991 115hp Johnson) idled great but would not go faster than 2000 rpms in gear, see the "Anita" thread going on right now for the details.

re: "Back at home with a flashlight I found that spark plug that came up clean before has a puncture in the boot on the coil, which directly lines up with a bolt on the clamps that secure the cowl"

Regarding the reference "ref:", you just reminded me of something I didn't mention in the Anita link, the cowl thing happened to me too! Once I had the engine finally fixed, and in the water test it it took off like airplane (the boat flies!), I then slowed down to adjust the idle speed, and removed the cowl. Upon setting the idle speed, I sped up again and the engine would not run fast again. After a lot of going back and forth thinking I realized that the engine cowl rear latch was grabbing and taking off the spark plug wires. I kept putting them back in and then when I put on the cowl it would take even more spark plug wires off, it was crazy. I took the boat home, looked at the picture in the manual of how the coils are installed and the spark plug wires are routed and found that someone had installed the coils facing the wrong direction and they made the spark plug wires more exposed to the latch. Therefore, I changed the coils and wires to the original direction same as the manual and made sure they were not catching the latch. Nevertheless, the latch cowl design is not a good one and one has to still be extremely careful when installing the cowl. As a matter of fact, I avoid altogether taking the cowl off in the water, because you can't see well the stern of the engine when you are installing the cowl from the front. When you install it on land you can do it from the rear and pay close attention that the latch does not catch any wires. NOW, here is something very important that helps a ton, I duct taped parts of the latch to make it more difficult for it to catch a wire when you slide it into place, and I used a lot of zipties on all the other wires back there (not the the spark plug wires, as they have there own spark plug lead clamps that guide them) to tighten up the wires. It is about all you can do, the latch design is lousy.

Re-oriented offending coil and replaced spark plug wires and she is running nice.

Took the boat out of a run and now I'm contending with other setup issues, namely a nasty porpoise that I'm attributing to a lack of negative trim.. But engine-wise is running well.

Not sure how it ends up this way but basically trimmed full down is still like having the engine somewhat trimmed up, something between the transom angle and changing engines, guess this vintage Johnson's don't have the same negative trim as Merc's..

Unrelated the engine raises up in reverse, think that's isolated to one of two valves - going to add some wedges and get the trim straightened out while the engine is hanging - then hopefully good to go!