Update on 65hp johnson: Help!

ShawnQ · Jan 19, 2003

Today I took it out for the first time, and when in neutral, it will free rev just fine, High RPM's, sounds good and clean, no missing, etc.. Once it is in gear, it sounds like it is only turning about 1/4 throttle...even when you've got it all the way down. Also, if you are driving it full throttle for a while (even though it is only going 1/2 speed), and you try to let off of it to slow down, it will die. You have to rev it up to get it into gear without it dying as well (which isn't good on the gearbox I know). Any more ideas? Thanks! Shawn

plywoody · Jan 19, 2003

Re: Update on 65hp johnson: Help!

Is this part of a previous thread? What have you done to it to this point? John

ShawnQ · Jan 19, 2003

Re: Update on 65hp johnson: Help!

Well, I haven't done anything to it yet. The reason why my previous thread didn't get me anywhere was because I had just bought the boat, and the previous owner could only tell me what it was doing... Without me ever experiencing it myself, I was having trouble explaining the problems. I figure with the symptoms I have posted above, I can get a little bit more help. BTW, it also smells rich. I will probably pull wires tomorrow to see if it effects running, as well as check the plugs for rich/lean. Thanks! Shawn

Walker · Jan 19, 2003

Re: Update on 65hp johnson: Help!

Shawn, tear the carbs down and soak them in carb cleaner then blow them out with air. Put in new plugs (L77JC4 Champions) gapped at .030. Make sure the timing is advancing. This should get you going unless you have a bad cylinder. Have you done a compression check.

ledgefinder · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Are all three plugs firing?

ledgefinder · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Are all three plugs firing?

dkondelik · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Without having a great deal of detail, go with what Walker stated. In particular, check the compression (I've seen similar symptom on motors with a bad cylinder). All cylinders ought to read within 10% or so of each other. If you have "dropped" a cylinder, pull of exhaust cover(s) and inspect the cylinders/pistons. If cylinder/piston is scored, then.... If a cylinder is down and there is no evidence of scoring or breaks, push on the piston rings to verify if stuck or not. If stuck rings, then decarb will probably help. Keep us posted of findings. Good Luck HAVE FUN!

plywoody · Jan 20, 2003

Re: Update on 65hp johnson: Help!

I would get a manual for your motor to start with. Be careful "soaking" carbs, as on some models this can dissolve seals in the carb and can cause further difficulties. My guess is that at least one cylinder is not producing power. Do a compression test to make sure all three cylinders are getting proper compression, and check spark on all cylinders. Let us know what you find. This condition can be caused by any number of things, and you have to start ruling things out as the problem. Good Luck! John

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

UPDATE! Today, after work I went ahead and connected the water hose adapter (I don't remember the 'lingo' name for this device). Anyways, I went ahead and fired it right up (Idles smooth, starts up on the first turn after you choke it once). I let it warm up for about 15 mins, and I could touch any and every part on the engine without any burning, barely even warm. After a quick visual, I noticed that the plastic around the coils have cracks around them, on all three coils. It appears that there is a clear silicon on them, not sure if it was put over them to try and seal the crack, or if it is from the inside out...but it is not sticky, just silicon like. Other than that, no oil leaks I can see, nothing unusual, just evidence that someone has been inside it before (new gaskets). Then I decided to start testing things.. DECIDED TO PULL PLUG WIRES AS FIRST TEST: NOW, here's what I found out. Pulled the top plug wire, nothing happened, still idleing the same, as smooth as it was before..dead cylinder? Pulled the middle plug wire, it dies. Live cylinder! Start it back up with just the middle plug and the bottom plug wire attached, and go to pull the bottom plug wire. When I pull it, it shocks me (scared me at first, hehe), but didn't do anything to the engine. However, anytime I touch that plug wire, I get shocked. (bottom cylinder, #3 I assume?) In conclusion, I think I am running on only one cylinder, the middle one. The top cylinder didn't shock me at all, so maybe the coil is totally bad, not sending any power to the plug wire. The bottom cylinder is shocking me, so it is getting power through it...whether it is shorted or not, I dont know...but it ran the same without it attached, so it can't be firing the plug..and must be a dead cylinder as well. So, what can it be? Dead coils? Bad contacts? I still haven't cleaned the carbs or checked compression, but there is an obvious problem here...so I need to address it sooner or later. If anyone can help me out, I'd greatly appreciate it. Thanks for your time, and this board is a great tool! Shawn

DJ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Shawn, Good diagnosis. Now, check, or get the compression checked. No sense fooling around with electrical if you have a sick engine. If that's OK, then I highly suspect your coils and plug wires.

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

What is a good compression reading for this engine? 65hp 72 Johnson... What are symptoms for bad compression? What causes it? What can be done to fix it? Just curious... I know on a typical engine/4 stroke, if it's got bad compression, it needs rings or a valve job, same way with the marine outboards? If there is bad compression, it would still spark...so I guess if I try looking for spark, and checking to see if they are the same intensity (in the dark, check the brightness), then I can at least find out if the spark is bad also... But, there is obviously a problem with the top and bottom cylinders if I can take the plug wires off and not have a problem.. Thanks! Shawn I don't remember now if I had

rickdb1boat · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Hi ShawnQ, Sure sounds like you need some wires! Compression on the older motors can be as low as 90 PSI and still run fine. The question is, are the cylinder readings within 10% of each other? That's what is important at this point. Unless of course, they're all 60 or something real low like that. Let us know. PS- Rings are the main cause or scored cylinders. Defective pistons will show major differences in the readings.

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

The engine was recently gone thru (I can tell because of the gaskets that I can see are not originals, and are not at all old looking (look very fresh.) Now, whether or not they tested the compression, or just did something else, I'm not sure... But, I'll check compression ASAP. I am going to pull the plugs themselves in about 1/2 hour, just after dinner. We'll see how they look. Another question, why would that one plug wire spark me, and the other two not make a difference at all? Shorted? Just curious... Thanks! Shawn

Solittle · Jan 20, 2003

Re: Update on 65hp johnson: Help!

The compression check is a must as others have noted. For a quick check of the electrical, pull the plugs out, reattach the plug wires to the plugs and ground the plugs to the motor. Hit the key and look for presence, color and intensity of the spark. Best to do this at night as you should also be able to see any arcing around the plug wires & coils.

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

I also forgot to mention that I burned ~4.5-5 gallons of fuel in only about an hour of runtime...if that helps anything. I am headed to my shop now to play with it some more. I am going to go ahead and pull the plugs, check them out, and check for spark/intensity/color/and any arcing. I am also probably going to check compression...if the tester I have will work. Thanks again, any other ideas are appreciated! Shawn

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Tested Spark and Compression! Well, the top two cylinders are in good shape, both reading in dead on at 125p.s.i.

As for the bottom one, not so good...the best reading I got on it was just above 28p.s.i., almost 100PSI off

So, what do I do about the compression, tear it apart and check out the cylinder/rings? Could it be something simpler, or is this pretty much a dead giveaway that it needs to be gone thru? I did notice that the piston looked quite dirty inside there...but I couldn't see the cylinder walls. If I run some of the engine cleaner, will it get any better, or is it too far gone? I did test the spark on all three plugs, and it seems as if all three are firing. (Pulled the plug, plugged it in, and grounded it on engine.). Each plug arced over to the engine, all about the same, and a bright blue/white arc. The three plugs all looked about the same (fouled according to my manual), with the bottom one (lower compression) being a good bit wetter than the other two, and had a much stronger gas scent to it. Here's a pic of the center cylinder's plug (good compression plug):

I also noticed, that when you turn the key over, there is an arc jumping between all three coils, from one coil to the other, and onto the metal bracket that holds the plug wires. This can't be good! It could be caused by the cracks in the coil casing, or something else...I'm not sure. Here is a pic I made of the whereabouts of the arcs jumping on the coils:

What kind of problems would that cause, weaker spark? Lastly, here is a close-up of the crack on one coil, there are several all the way around each coilm this one is probably in the best shape of the 3:

Thanks for any hints/help/ideas...I appreciate it! Shawn

OBJ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Hi Shawn... Your getting zapped because the cracks in the coils probably go down to the coil its self. Maybe your whole problem. Anyways..install new coils and go from there. OBJim

OBJ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Neat pictures to!!!!! OBJim

ShawnQ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

what about the compression prob on the bottom cylinder? Shawn

OBJ · Jan 20, 2003

Re: Update on 65hp johnson: Help!

Sorry Shawn...missed that one all together. You need to verify that the cylinder is shot or maybe rings are stuck. Low compression like that compared to the others and I would say you may have scorring in the cylinder. The exhaust cover can be easily removed to get a look at the cylinder. Just a bunch of bolts to remove. Check it out before you go anyfurther. OBJim

Update on 65hp johnson: Help!

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