33 hp Johnson doesn't sound right, video what do you think?

Just threw this on our 14' yar-craft, its probably a little smaller than the boat should have but it was what the budget called for. Anyway after running around about half an hour to 45 minutes it just didn't sound right to me, do you think its sucking for air, gas, to rich, to lean, to something?

Hope the video helps

Re: 33 hp Johnson doesn't sound right, video what do you think?

What throttle position was that? Sounds like its running on one cyl.

Re: 33 hp Johnson doesn't sound right, video what do you think?

HI diveman. I used to have a '66 33 hp myself. It definitely did not sound like that :/ Based on the knocking, I think you may only be running on one cylinder. I would check the compression on each cylinder. They should be over 100 psi and within 10% of each other. If the compression is ok, then I would check the ignition for spark that jumps a 1/4" gap with ease. These links can walk you through a basic tune up from top to bottom.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://forums.iboats.com/showthread.php?t=167352

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

Re: 33 hp Johnson doesn't sound right, video what do you think?

kfa4303 said:

HI diveman. I used to have a '66 33 hp myself. It definitely did not sound like that :/ Based on the knocking, I think you may only be running on one cylinder. I would check the compression on each cylinder. They should be over 100 psi and within 10% of each other. If the compression is ok, then I would check the ignition for spark that jumps a 1/4" gap with ease. These links can walk you through a basic tune up from top to bottom.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://forums.iboats.com/showthread.php?t=167352

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

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Thanks for the great links, i will get on this and keep you guys updated, to the post above that was WOT.

Re: 33 hp Johnson doesn't sound right, video what do you think?

kfa4303 said:

HI diveman. I used to have a '66 33 hp myself. It definitely did not sound like that :/ Based on the knocking, I think you may only be running on one cylinder. I would check the compression on each cylinder. They should be over 100 psi and within 10% of each other. If the compression is ok, then I would check the ignition for spark that jumps a 1/4" gap with ease. These links can walk you through a basic tune up from top to bottom.

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm

http://forums.iboats.com/showthread.php?t=167352

http://www.outboard-boat-motor-repa...on 3 HP 1952-1967 Ignition System Tune-up.htm

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

Click to expand...

so i've got spark, i had one of those testers, i have to rent a compression tester from autozone tomorrow, i did notice that my bottom cylinder the spark plug was very dirty and oily. The previous owner said he had very recently changed them.

The engine seemed to run good for a while then after over 1/2 hr of running it started knocking, so basically after it was fully warmed up. I guess the question is after i check compression if that is good is it more likely to be running rich maybe or should i try and replicate the problem and then see if the bottom plug sparks after it starts with the problem again?

Re: 33 hp Johnson doesn't sound right, video what do you think?

Hello again diveman. For starters, make sure you're running the correct plugs. Champion J6C are best. Both cylinders are feed fuel, more or less equally, so if one plug is particularly fouled it's probably not firing consistently which means you'll have to inspect the ignition. The fact that it happened after the motor warmed up is also a tell tale sign that you have an ignition/electronic problem. As the motor heats up, it causes the components to fail. You may also want to make sure the spark plug wires are twisted into place onto the coil posts rather than just poking them in place. If the plug wires are corroded, you may want to snip them back about 1/2" on the coil end to expose some fresh copper within. Btw have you inspected the coils? If they are scorched or cracked in any way they will need to be replaced as well. Of course a carb cleaning and rebuild is never a bad idea, but focus on one factor at a time. Once you have strong, consistent spark, adequate compression and fuel, it should fire right up. You can get a tune up kit with points & condensers as well as new coils right here at iboats for about $20 each. Keep us posted. Holler if you get stuck.

Re: 33 hp Johnson doesn't sound right, video what do you think?

kfa4303 said:

Hello again diveman. For starters, make sure you're running the correct plugs. Champion J6C are best. Both cylinders are feed fuel, more or less equally, so if one plug is particularly fouled it's probably not firing consistently which means you'll have to inspect the ignition. The fact that it happened after the motor warmed up is also a tell tale sign that you have an ignition/electronic problem. As the motor heats up, it causes the components to fail. You may also want to make sure the spark plug wires are twisted into place onto the coil posts rather than just poking them in place. If the plug wires are corroded, you may want to snip them back about 1/2" on the coil end to expose some fresh copper within. Btw have you inspected the coils? If they are scorched or cracked in any way they will need to be replaced as well. Of course a carb cleaning and rebuild is never a bad idea, but focus on one factor at a time. Once you have strong, consistent spark, adequate compression and fuel, it should fire right up. You can get a tune up kit with points & condensers as well as new coils right here at iboats for about $20 each. Keep us posted. Holler if you get stuck.

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I found my project after work thank you for all your help, i also have an added project, i found when i took out the plugs the previous owner must have cross threaded the top one as when i tried to put it in it was stripped... so looks like the head is probably coming off which means i'll take a look at everything inside there and replace the head gasket too, probably not to bad of a thing to happen or to replace but what a pain! Thank you again for all your help!

Re: 33 hp Johnson doesn't sound right, video what do you think?

Hello again diveman. Before you remove the head gasket, try installing a Helicoil into the old, stripped spark plug threading. Do a search here in the forums for the How-to posts. Lots of folks have had good luck with them. Best of all, they're cheap and may save you a ton of work.

Re: 33 hp Johnson doesn't sound right, video what do you think?

kfa4303 said:

Hello again diveman. Before you remove the head gasket, try installing a Helicoil into the old, stripped spark plug threading. Do a search here in the forums for the How-to posts. Lots of folks have had good luck with them. Best of all, they're cheap and may save you a ton of work.

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I've been reading those all morning actually, i think i'm going to give it a try...

On a side note you mentioned you had a 33 hp engine, how big of boat was that on? I ask because this one just seems to have no power, which is where we are going with the running on one cylinder, but based on your experience do you think it will be enough for my 14' yarcraft to at least plane out and cruise around after i get it running properly?

Re: 33 hp Johnson doesn't sound right, video what do you think?

I had mine on a tiny little 14' fiberglass skiff and it was scary fast (over 30 mph). My current '66 20 hp pushes me along in my 14' semi-v tinny skiff at about 20 mph +/-, so that old 33 hp should get you closer to the 25 mph range when properly dialed in and it should easily get on plane with you and 1 or 2 other folks on board. My 20 hp even got my boat on plane with 3 people. It didn't like it, but it did it. Once it's firing on all (both) cylinders, you'll notice much better performance. Make sure the anit-vent plate found just above the prop is level, or slightly higher than the bottom of the boat. I actually just made a jackplate/transom riser to get my motor to the correct height as OMC motors of this era have a sort of olng leg on them which causes excess drag.

Re: 33 hp Johnson doesn't sound right, video what do you think?

kfa4303 said:

I had mine on a tiny little 14' fiberglass skiff and it was scary fast (over 30 mph). My current '66 20 hp pushes me along in my 14' semi-v tinny skiff at about 20 mph +/-, so that old 33 hp should get you closer to the 25 mph range when properly dialed in and it should easily get on plane with you and 1 or 2 other folks on board. My 20 hp even got my boat on plane with 3 people. It didn't like it, but it did it. Once it's firing on all (both) cylinders, you'll notice much better performance. Make sure the anit-vent plate found just above the prop is level, or slightly higher than the bottom of the boat. I actually just made a jackplate/transom riser to get my motor to the correct height as OMC motors of this era have a sort of olng leg on them which causes excess drag.

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Thats good to hear, we were jelous out on the lake yesterday trying it out getting buzzed by 25 hp pontoons, i look forward to this project and getting it running! Thank you again for all your help, i'm sure i'll have more questions and will keep you updated! thanks again!

Re: 33 hp Johnson doesn't sound right, video what do you think?

My schedule got crazy and i cheated and had my local small engine guy get this up and running and it sure did need a lot! but after a installing a helicoil for the thread, putting in new spark lugs, new points, new head gasket, doing a little fixing on the timing and some carburetor work we are up and running it sounds like... Thank you everyone for the advice as it helped him to start with and get everything fixed right...

Now i'm just wondering about a charging system on this motor, does it have one? I've read that they don't?