Johnson QD15 extremely hard to pull start

Hey Guys,

I am having a heck of a time. First off I am brand new to working on boats, but I have a lot of experience(college) working on 4 stroke car motors and pretty good "mechanical sense" if that is a term. I recently moved to a lake and am restoring an old 14 foot aluminum boat to fish with. I came across a 1954 johnson qd-15 2-stroke outboard motor that has been sitting for, perhaps, 15-20 years and am going to use it, in conjunction with a trolling motor, on the fishing boat. The motor has good compression, new coils, points, condensers, plugs, impeller, rebuilt carb. When I initially took the lower unit off it had squirrel nests in it. Here is the issue, I put everything back together put the engine in a barrel of water hooked the tank up with fresh gas/oil, I went to pull and I gave it all I had and the motor is, what I would consider, abnormally hard to pull. So I took the lower unit off thinking the shaft was bound and, with the lower unit off, attempted to pull the motor over(with fuel line unhooked just incase). The motor is still entirely too hard for me to pull over (6'1" 240 26 years old who is in decent shape). So I started inspecting things I took the recoil off, with the lower unit still off, and turned the flywheel slowly, I could hear hissing every half turn or so and got some leaking (of penetrating oil that I sprayed into the cylinders I think) onto the ground. I took out the old spark plugs to replace them with some new ones and just for the heck of it tried turning the flywheel. With the spark plugs out the engine is, perhaps, 10x easier to turn over. My question is: What can I do to make this engine easier to pull over. Does it need a valve job? Does it have valves? Could exhaust/intake ports be clogged or laced with carbon? Has anyone experienced this before? I've been lingering around this website getting free info, but can't seem to figure this out.

Thanks,

Kpowell

Re: Johnson QD15 extremely hard to pull start

Did you notice this before you took the gearcase off?

Im assuming you would have noticed as you said you checked compression, and Ill assume all was well then?

Re: Johnson QD15 extremely hard to pull start

I didn't notice it being so hard to pull when hooked up the the compression gauge, however I was not trying to start it then. I would say there is little difference in the effort required to turn the motor from when I first did the compression test(before I spent any money), and now.

Edit: compression tested around 65 in each cylinder which I read is enough to at least get it running.

Thanks,

Kpowell

Re: Johnson QD15 extremely hard to pull start

It could be the coils are improperly installed and rubbing on the flywheel. Don't ask me how I learned that one. LOL. Best of luck. Rick.

Re: Johnson QD15 extremely hard to pull start

I can check that installation of the coils, however I installed them cautiously by replacing part by part at a time to ensure things went back in exactly how they came out. Thank you for the idea, I'm still thinking it's compression related secondary to the fact it's easier to turn over with the cylinder not sealed (plug out).

Thanks for the idea,

Kpowell

Re: Johnson QD15 extremely hard to pull start

Here is a link to a post in the top secret files. It shows how the coils should line up with the mounting bosses. You can use a ruler to help true them up against the mounting bosses.

http://forums.iboats.com/engine-fre...-change-coils-set-points-old-omcs-294072.html


The guys are right, your coils heels may be rubbing up against the flywheel. Don't worry a little rubbing of the coils and flywheel shouldn't do much damage. I think you will be fine there, but I would not do any more tugging on the starter or turning of the flywheel until you have that verified.

Leave the lower unit off for now until you verify that it is it is just the coils rubbing up against the flywheel.

Please mix your fuel no leaner than 24:1.


I have a 1954 10hp QD15 that I am mechanically restoring. What are your compression numbers prior to the motor rebuilding??

Post some pics if you can!!

Re: Johnson QD15 extremely hard to pull start

I can check that installation of the coils, however I installed them cautiously by replacing part by part at a time to ensure things went back in exactly how they came out. Thank you for the idea, I'm still thinking it's compression related secondary to the fact it's easier to turn over with the cylinder not sealed (plug out).

Thanks for the idea,

Kpowell

Click to expand...

Compression and having the plugs in should not cause hard starting. The usual compression for those motors is about 75 to 90psi. I have a 1955 15hp Fastwin with about 120psi on each cylinder and it is not hard to pull over. I'm 5'11" and 184lbs and the starting is easy, so please check under your flywheel.

Even though we carefully put things back, we all sometimes make mistakes. You could have forgotten to snug down one of those coils or did you torque down the flywheel to 40 to 45 foot pounds. Check also for wires being loose or catching on things.

Good luck, I hope you resolve this quickly and get her running!! Awesome motor!!

Re: Johnson QD15 extremely hard to pull start

I'll surely check the coils tomorrow to make sure they are flying true. My fuel mix is 16:1(that's what the original tank suggested). The engine is sort of ugly, it was painted black over the original green, but I can post pics before and after I paint.

I was reading on a different forum about an "Idle pressure relief" that may clog. Does anyone know where I may find this and what covers I need to remove to access it?

Thanks for the responses,

Kevin

Re: Johnson QD15 extremely hard to pull start

It will always be much easier to spin with the plugs out, that is the nature of the motor. Very normal.

It is very hard to guess as we are not there to physically feel it ourselves. Is the motor on a sturdy stand? What seems hard to pull on a flimsy stand is easy on the transom of a boat. Just a thought.

Re: Johnson QD15 extremely hard to pull start

cajuncook1 said:

Compression and having the plugs in should not cause hard starting. The usual compression for those motors is about 75 to 90psi. I have a 1955 15hp Fastwin with greater than 120psi on each cylinder and it is not hard to pull over. I'm 5'11" and 184lbs and the starting is easy, so please check under your flywheel.

Even though we carefully put things back, we all sometimes make mistakes. You could have forgotten to snug down one of those coils or did you torque down the flywheel to 40 to 45 foot pounds. Check also for wires being loose or catching on things.

Good luck, I hope you resolve this quickly and get her running!! Awesome motor!!

Click to expand...

Can you think of why there is such a difference with the plugs in vs them out? I did over torque the flywheel Thank you for the info. I surely am not overlooking the fact that I could have installed the coils wrong, I am going to check them tomorrow. I am just trying to get all ideas possible so I can address them all in one swoop.

Thanks for the helpful info,

Kpowell

Re: Johnson QD15 extremely hard to pull start

HighTrim said:

It will always be much easier to spin with the plugs out, that is the nature of the motor. Very normal.

It is very hard to guess as we are not there to physically feel it ourselves. Is the motor on a sturdy stand? What seems hard to pull on a flimsy stand is easy on the transom of a boat. Just a thought.

Click to expand...

I made a stand out of 2x4's. Not quite a transom sturdy, as it is on casters, but fairly stout. I still feel like even if it was attached to a brick wall I would not be able to pull it hard enough for it to move over an inch past the end of the rope, maybe it's time for me to hit the gym again .

Thanks for the idea,

KPowell

Re: Johnson QD15 extremely hard to pull start

With the plugs in you have full compression necessary for operation. With them out, you have 0 compression, and no resistance.

Re: Johnson QD15 extremely hard to pull start

You motor does not have the compression relief, that was with larger motors with higher compression.

Do you have a 4 gallon or 6 gallon tank.

The 4 gallon tank was sold with the 5.5 and 7.5hp Evinrude and Johnson motors. Those motors had bushing connections to the crankshaft, so they required higher fuel to oil ratio mix to prevent premature wearing and damage. So, those tanks were sold with the instructions to mix at 16:1 ratio.


The 6 gallon tank was sold with the 10hp, 15hp, 18hp, 25hp, 30hp and 35hp Evinrude and Johnson motors. Those motors had bearings connections to the crankshaft, so they had less of a fuel to oil ratio mix to prevent premature wearing and damage. So, those tanks were sold with the instructions to mix at 24:1 ratio.


But, running your motor at 16:1 ratio will not harm it in the slightest. The extra lubrication will help protect the motor. Today's TC-W3 oil are far superior to the plain non detergent 30wt oil mix with gas back then.

Re: Johnson QD15 extremely hard to pull start

Here are some charts with information that is often asked by visitors or members. I thought I would just pass along the information.

With the computer mouse, just left click once the picture to isolate it and then with the computer mouse right click on the picture and choose option ( save image as) to download it on your computer for future reference. You enlarge the picture on your computer for better viewing.


[highlight]Power head torque information:[/highlight]

[highlight]
Piston and ring clearance:[/highlight]

Re: Johnson QD15 extremely hard to pull start

It must be the 4 gal. because it says 16:1, thanks for the info on not having compression relief and about the fuel tanks. Looking like the coils or my 90 ft/lb torque job on the fly wheel (Doh!).

thank you everyone for the info,

Kpowell

Re: Johnson QD15 extremely hard to pull start

Re: Johnson QD15 extremely hard to pull start

cajuncook1 said:

Here are some charts with information that is often asked by visitors or members. I thought I would just pass along the information.

With the computer mouse, just left click once the picture to isolate it and then with the computer mouse right click on the picture and choose option ( save image as) to download it on your computer for future reference. You enlarge the picture on your computer for better viewing.


[highlight]Power head torque information:[/highlight]

[highlight]
Piston and ring clearance:[/highlight]

Click to expand...

Fantastic!

Thanks,

Kpowell

Re: Johnson QD15 extremely hard to pull start

When you remove the flywheel, take pictures of your ignition plate, crankshaft, and underside of the flywheel, so we see if there is damage.

We all learn at some point, so be patient and ask a lot questions. That why the forum is here!!

Re: Johnson QD15 extremely hard to pull start

90 ft/lbs! Yikes.

I dont know if you want the answer to your problem

You may have ruined the flywheel. Time to pull it and see what is going on.

Re: Johnson QD15 extremely hard to pull start

HighTrim said:

90 ft/lbs! Yikes.

I dont know if you want the answer to your problem

You may have ruined the flywheel. Time to pull it and see what is going on.

Click to expand...

Certainly hope not, but if I did I bet I wont ever do it again. I will post pics tomorrow and we'll see the damage. Looks like I might be rebuilding the mercury mark comet 6 if I messed this up.

Thanks,

Kpowell