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Message
Small outboard motor gurus
Posted on 9/28/16 at 7:47 am
Posted on 9/28/16 at 7:47 am
Have a 1985 Johnson 25hp. Been running ok till the other day, had issues with motor seeming to fire on one cylinder and then dying. Would not restart. Had to be towed in. Mechanic changed power pack and some other electrical connectors that had corroded.
Motor ran fine for two days and then yesterday started running poorly, would completely bog down to almost just above idle speed, would not throttle back up. Got the thing back to the dock, running ok at very slow speed. No smoke, water pump pissing good stream. Checked plugs and both fouled, bottom plug really oily and fouled. Changed plugs but only tested at idle. Will take out to run or try to run at higher speed.
Any ideas of the cause of the motor bogging? Running 100:1 mixture in gas. TIA.
Motor ran fine for two days and then yesterday started running poorly, would completely bog down to almost just above idle speed, would not throttle back up. Got the thing back to the dock, running ok at very slow speed. No smoke, water pump pissing good stream. Checked plugs and both fouled, bottom plug really oily and fouled. Changed plugs but only tested at idle. Will take out to run or try to run at higher speed.
Any ideas of the cause of the motor bogging? Running 100:1 mixture in gas. TIA.
2
Posted on 9/28/16 at 8:05 am to canyon
How old were them plugs to begin with? We change them out every year no matter what. 100:1 is too thin your gonna scortch a cylinder go 50:1. Bogging could be dirty or gummy carbs, bad firing time, bad link and sync on carbs, bad ground, fouling power pack too much to just diagnosis over a key board. Clean them carbs up and put rebuild kits in them if you have ran any ethanol fuel in a 1985 engine is NO BUENO. Link and sync them to the timing. That doesn't take long and will help start eliminate a laundry list of problems that could be the issue
This post was edited on 9/28/16 at 8:07 am
Posted on 9/28/16 at 8:15 am to Boat Motor Bandit
Plugs were probably a year old but can't attest as I bought it last December.
thanks....should have edited, i am running 50:1
Lots of things to consider, need to start with carb. Am running marine gas in the tank. Power pack brand new, so I'll start with other suggestions.
thanks again.
thanks....should have edited, i am running 50:1
Lots of things to consider, need to start with carb. Am running marine gas in the tank. Power pack brand new, so I'll start with other suggestions.
thanks again.
Posted on 9/28/16 at 8:23 am to canyon
Honestly with a motor that age, lots of electrical problems start to pop up. brittle and internally corroded wiring is a real issue with a 30 year old motor. Internal carb issues as well those brass jets get brittle the float will start to crack, chip, actually become water logged with fuel. So many things to keep in mind. Take your time and check it all good.
Posted on 9/28/16 at 8:34 am to canyon
There is only one thing that can cause oil fouled plugs on a 2 stroke, and that's low combustion temperatures.
Are you putting a lot of strain on the motor by riding slow with a heavy load? If yes, that could contribute.
First things first, dump all that fuel out on an ant pile and start over.
Put a compression tester on it to rule out low compression and then work you way backwards.
If compression is good, check the plugs for the correct heat range.
Could be a jetting problem so double check your carbs and make sure they are properly adjusted.
When you use the motor let it run wide open throttle for a couple seconds on your way back to the ramp. This will help burn off all the doodoo that builds up in the cylinders and on top of the pistons. It will give you a performance base line to better help monitor slow developing issues.
Are you putting a lot of strain on the motor by riding slow with a heavy load? If yes, that could contribute.
First things first, dump all that fuel out on an ant pile and start over.
Put a compression tester on it to rule out low compression and then work you way backwards.
If compression is good, check the plugs for the correct heat range.
Could be a jetting problem so double check your carbs and make sure they are properly adjusted.
When you use the motor let it run wide open throttle for a couple seconds on your way back to the ramp. This will help burn off all the doodoo that builds up in the cylinders and on top of the pistons. It will give you a performance base line to better help monitor slow developing issues.
Posted on 9/28/16 at 8:37 am to canyon
1985 outboard ... it has had a good life might be time for a replacement. At that age you will be constantly chasing ghosts.
Posted on 9/28/16 at 8:46 am to bayoudude
believe me....I've been considering that.
thanks
Posted on 9/28/16 at 8:48 am to Barf
Good suggestions, thanks !
Not running on a heavy load, pushing 13' whaler, with generally just me or two in the boat.
when the motor runs it runs like a spotted arse ape
just so happens the gremlins have taken over!
Not running on a heavy load, pushing 13' whaler, with generally just me or two in the boat.
when the motor runs it runs like a spotted arse ape
just so happens the gremlins have taken over!
Posted on 9/28/16 at 8:55 am to canyon
That motor went relatively unchanged for something like 20 years. It's a good motor and assuming you don't have a bad ring it will most likely be a cheap fix. Even the rebuild kit on these things isn't too painful if you have a spare weekend and a case of gas station beers.
Normal idle and low speed operation with loss of power with throttle leads me to believe it's time for those carbs to be rebuilt. But before I did that I would test the compression. If the cylinder with the fouled plug is more than just a few psi off of the other cylinder, its time for a top end rebuild. Sounds scary but its really not a big deal. You can do it.
Normal idle and low speed operation with loss of power with throttle leads me to believe it's time for those carbs to be rebuilt. But before I did that I would test the compression. If the cylinder with the fouled plug is more than just a few psi off of the other cylinder, its time for a top end rebuild. Sounds scary but its really not a big deal. You can do it.
Posted on 9/28/16 at 8:57 am to Barf
Thanks Barf.
Glad for the info
You gonna be down in the lower Keys this weekend? I'll supply the beer
Glad for the info
You gonna be down in the lower Keys this weekend? I'll supply the beer
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