1985 85 HP Johnson Running Like a Three Legged Dog

[jiju1943]

We recently bought a used pontoon that has a 1985 85 HP motor on it. Yesterday was the first time we have taken it to the river. When I first fired the motor up, it popped and sputted like it had water in the gas. (it was hard to fire up) I know it didn't have water in the gas as I just bought the gas (not ethanol). The motor will not low idle, I have to keep the idle lever all the way up to keep it running and the only way to put it in gear without it dying is shut the idle down and just before it dies shove it in gear. Pretty tricky timing to keep the gears from grinding.

While it did run while giving it gas, it would die if the rpms got too low. It never opened up past half throttle, that was about as good as it got. I did take the carbs off and cleaned them with brake cleaner and blew them out. The carbs weren't too badly gunked up so I thought I was good to go. The needles looked to be in good shape also and all gaskets were rubber and in great shape.

Are there any adjustment screws on these carbs? I have another 85 HP Johnson that ran great when I parked it, maybe clean the carbs from that one might work. Also, we went about 4 or five miles down the river/lake at a low speed and we burned about 5 gallons of gas, is that normal? I haven't checked the compression yet but I will get a gauge and check.

Would seafoam help any?

 

[ahicks]

I'm assuming you bought this boat on the cheap, or you'd want to return it to the seller.

That being the case, I would start with a fresh set of plugs, and if that doesn't do it, a thorough cleaning of the carbs on THIS engine. See where that leaves you...

Best of luck.

 

[lmuss53]

Plus one for carb cleaning. There are low speed passages in these carbs that provide the fuel for the first 30 % or so of the throttle transition, sounds like they are clogged. Did you check float heights and needle valves? It sounds like you might have a stuck float, that is too much fuel for a 5 mile cruise.

 

[HotTommy]

More help is available here. Sea Foam won't hurt.

Second thought: If you bought this old, used engine and just dropped it in the water and fired it up, you may want to do some other preventive maintenance first. For example, check the oil in the lower unit, check the condition of the fuel hoses, etc. When I bought such an engine, I rebuilt the fuel pumps, cleaned the carbs, replaced the spark plugs and wires, replaced the thermostat, replaced the impeller, replaced the oil in the lower unit and checked the compression before I ran it. I'm not fond of getting stuck out in the water on a pontoon boat. They're not easy to paddle.

 

[jiju1943]

I did get a great deal on the boat, motor and trailer, the fellow I bought it from wouldn't have the money to give back even if I did want to give it back. The fellow told me he was putting this motor on the toon but never finished hooking it up. How long it had been since being cranked, I have no idea but I am sure it was over two or three years.

I just noticed that oil is leaking from the foot area so I am guessing a seal went down the tubes also. I will get new plugs, and I plan to use the carbs from my other motor, do a good cleaning on them and see how they work, if they work good that is fine, if not I will do a rebuild.

I did check and the motor is peeing like it should so that is a plus.

Just got some seafoam. I appreciate your time and help. I will let you know how it goes and what I found. Thanks a ton.

 

[lmuss53]

A little blackish oily discharge from the prop area is not unusual, especially on a boat you suspect might be getting too much fuel. It is unburned fuel that accumulated in the motor draining out, Don't assume there is a bad seal just yet, check the amount and condition of the lower unit oil first.

 

[lmuss53]

Pump the ball up hard and see if you can push fuel through a carb. If you have one float sticking the motor will run as you describe and use a ton of fuel. If you have a float not sealing off you can push fuel through that carb with the ball.

 

[jiju1943]

Imuss53, I really do appreciate that information, it is indeed black oil, I thought to myself, that has got to be some nasty looking gear oil, they must never have changed it. I will do a check tomorrow to see if the gear oil is that black, Lord willing.

I did change the carbs from my other motor today, I know they are in good shape and the gas from a few months back still smells and looks fresh. I didn't get to fire it up today but will put the muffs on and give it a try tomorrow.

 

[Mi duckdown]

First and always thing I do is check compression. Take that equation out. it cost nothing to do that

 

[1983 ercoa 21']

Plus one for the compression check before you do anything else. A dead cylinder will cause the same problem your having. If the compression checks good then do a cylinder drop test by running the motor and pulling each plug wire to see if there is a difference in the way it runs if no change then that cylinder is not firing. Also you might have better luck with this in the evinrude / Johnson part of this forum

 

[jiju1943]

Thank you guys so much for helping me out, I really do appreciate it. I have been reading some in the pontoon forum and am now really over whelmed with so much different information, but that is another story. I did fire the motor up today, I am happy to say it runs much much better, it will idle slow like it is supposed to. The main problem I am having now is it will pop or backfire through the exhaust and at the lowest idle the pop or backfire will sometimes kill the engine. I have changed out the coils on the right bank with no better results. I also bought new plugs and installed.

I noticed that the wire clip that goes on the plugs is very rusty on all of them, is there a way to change the plug wires or do I have to replace the entire coil? I thought I knew something about boats and pontoons after owning several, but reading here on Iboats I realize just how little I know. One more thing, I noticed that the plastic that covers the coil has a crack, is this bad or is it just cosmetic?

 

[HotTommy]

As a couple of us have already said, you'd get better answers to your motor questions on the motor forum part of this site.

 

[gm280]

WOW after reading all the comments thus far, I don't even know where to start. I would probably do the compression test first to verify you actually have an engine to support combustion and run. Then the carbs(s) would be next on the list. And that doesn't mean a little carb spray through them, but total disassembling them an installing carb kits and all parts that are suspect. Then fuel pump and fuel lines as well as plugs. And lower foot oil and water impellor. Trying to make it run by make-shifting things is not a good way to get it working properly. It needs some serious fixing presently. If you plan on using this for a quality power plant, then go over everything and make it right. Cleaning, adjusting and replacing bad and worn out parts is a good start... JMHO!

 

[lmuss53]

Excellent advice from gm280,

 

[jiju1943]

gm280, I really do appreciate the advice, that does make sense. I did a compression test and all 4 have 92 psi. I plan to take the plugs out, fill each cylinder with seafoam and let it sit for an hour or two and see if that will help bring the compression up any.

 

[lmuss53]

I'm pretty sure 92 is acceptable on that motor, they are not especially high compression motors. If it hasn't run in a while it will come up also. Now work your way down gm82's list. Go to the Johnson Evinrude page and read the sticky post on "awakening a sleeping motor".

 

[jiju1943]

Thanks Imuss53, I will check it out.

 

[MaPaHa]

I've always run older motors and one product that I use is Yamaha "Ring Free" treatment in the gas. It's about $50.00 a quart and you can run it for normal maintenance at an ounce or two per 10 gallons as listed on the bottle or you can step the mixture up for treatment. It's good for carbs but it keeps the varnish down on the rings. When I had the heads off of my 175 Johnson to change the O-Ring seals a couple of years ago I used it straight to clean the tops of the pistons with a parts cleaning "tooth brush" and the build up came off easy. If you have a half of a tank or so of gas you can get a treatment mixture without using as much. As I'm writing this, I'm reminded that it's time for some in the same 175 motor. My son and I took it out today and it was a little rough at idle and a low speed.

Keep in mind that a motor will idle better on a garden hose that it will in the lake if you are not hitting strong on all cylinders because of the back pressure of a couple feet of water against the exhaust. With that kind of compression, I'd run a double to triple dose of ring-free for several outings and see what happens.

 

[jiju1943]

Thanks MaPaHa, they are kinda proud of that stuff aren't they. I too feel the rings have set with the compression no higher than it is. There are a couple things I want to try before I try the Ring Free. Deep Creep by Seafoam was recommended to do the same thing so I will give that a try first. I am sure the ring free works like a charm, and I really do appreciate you letting me know about it. If the Deep Creep doesn't work I will give the Ring Free a try.

Jim

 

[jiju1943]

Here is the latest situation on my motor. I want to do a catch up on my progress, then later I will do a followup. I got so discouraged with the Javlin motor that I took it off Saturday. I had taken it to the lake 4 times and as I stated earlier, the motor used a tremendous amount of gas in about 4 miles or so. Black oil was dripping out the exhaust and the motor would backfire through the exhaust, that was the only time we have been out on the boat.

I made several attempts to correct the problem and back to the lake 3 more times.

Here is what I discovered, I took the flywheel off to check the timer base and make sure it was advancing properly. In doing so my grandson wanted to help and he is bigger than me so I let him. LOL He tightened the nut on the flywheel and I had changed the plugs, changed plug wires, cleaned the carbs well, and ran the engine on muffs. While the backfire was still there every once in a while, we went back to the lake.

The engine fired up and ran for a short while and backfired several times. The engine quit after a heavy backfire and would not fire up again. Back at the shop, I did everything I could think of to get the motor to fire up, nothing but a very heavy kickback like it had jumped time. I was about to give up and just for the heck of it pulled the flywheel again, the Woodruff key had sheared and the engine had for a fact jumped time.

I replace the key and it did fire back up, but still backfired. To me the engine just didn't seem to have the power it should. I finally decided to take the engine off and put my standby motor on, that I had taken off my old bass boat, which happens to be the same motor as the Javlin except it is a low profile. By the way, the Javlin is a 1976, not a 1985, as I discovered, the low profile motor is a 1975.

I put the low profile (or green engine) on the pontoon along with a jack plate. I installed a jack plate because my tilt and trim would not fit other wise. As I was taking the power pack off the Javlin (white motor) I noticed the #1 and #3 coil wires were backwards. I did change the power pack but the way I changed it, it was impossible to get any wires crossed as I removed one wire at a time then put on the other power pack. Also the motor had backfired from day one. There was the trouble all the time crossed coil wires on the power pack, after all that trouble the problem was discovered.

I will not put the white motor back on, I will use it for parts. Now to drop the foot and adjust the shift rod on the green motor and change out the impeller. Looks like I may be on the right track for a change. I will let you know how things go.

Thank you all so very much for your help and advice, I very much appreciate it.

Jim