This is my very first boat... So I'm completely new to all of this...But, I bought a '92 Cajun with a Johnson 115 yesterday. I took it to the lake today to test it out and it wouldn't stay running. It runs if I give it throttle in gear, But it won't idle. So it dies when I turn the throttle down.

Here's what I know about it:
~Had a little old gas in it...So I added about $30 of 91 octane.
~The plugs look like they're probably new (from what I can tell without taking them out)
~The guy I bought it from seemed really honest, and said the engine ran great.


What can I try? Where should I start?
My kids were so excited to get to go to the lake in the new boat...so it kinda sucks that we can't even get it off the trailer. Any advice will be greatly appreciated!
Thanks, John

Too me it sounds like all it needs is the carbs gone through, but I'm far from being an expert!!!!

How long as the boat been sitting?

Try some Seafoam in the gas. No mechanic but that might help if you can get it running and launched to burn some gas/Seafoam through it.

Not sure how long it's been sitting... I would guess atleast all winter... but he did say he took it out over the weekend and that it ran fine except for the bad gas.

where can I get some Seafoam?

I'm gonna run out and see if I can clean up the carbs, without messing anything up.

Hachie,

Before you run it, find out if the boat has sat up for more than 2-4 months. If it has, trust me on this, have the carbs broken down and cleaned. The reason why? If you're carbs are clogged, you're starving the engine from fuel. When it is starved for fuel, it is also starved of oil. You can damage your engine more by trying to "run it out" or running it hoping the problem clears itself up. I've learned the hard way over the years, that problems with engines just don't cure themselves.

So take it in and have it looked at. The money you spend now will be MUCH cheaper than the alternative.

did you test the boat out before you bought it.

Sounds like the low speed idle jets are clogged.

i agree with Michael,if it's not getting the right fuel mixture then it's not oiling right.having the carbs done not is not all that expensive.rick

John,

Please do what Michael suggested. Did you take it for a test drive before you bought it?

I agree with the folks above on the carbs needing cleaning. Doing the carbs isn't that hard if you have the tools, time and some mechanical capability. Get an OEM manual if you're going to try and work on it. Seafoam might help if the carbs aren't too gum'd up. That motor has a VRO system (Oil Injection) unless it's been disabled. Is the VRO still in tact? How many owners? Is there an hour meter on the boat giving an indication of how many hours the engine was on? Compression check? There are lots of things. If it has been well cared for it should be fine with minimal TLC. When in doubt take it to a reputable shop and have it checked. I can't make a recommendation since I work on my own. I will tell you that I will drive 100 miles for the comfort of knowing that the shop is not going to rip me off or damage my motor or boat. There are a lot of shady places. Just read some of the other posts about service complaints.

I'm still waiting to hear if you ran it before you bought it...

For sure the carbs.....DO NOT RUN THE ENGINE!!!!....... Have it checked out, you never know, it might just be a sparkplug. You might have knocked a plug wire off when you replaced the cowling.A simple check is worth a thousand$$$$$$$

play it safe take it to a mechanic if you run it lean because of stopped up carbs your gonna kick a rod

Ok... I took of both carbs and they were both really clean. Looks like they've been cleaned very well recently. I went ahead and cleaned them again with some chem tool. I also took the plugs out and was going to replace them, because they were black and gummed up, but not burnt. But my auto supply shop didn't have any in stock. He picked em up and smelled em, and immediately said "I'll tell ya what your problem is... It's old gas". He said he could smell it on the plugs. I went ahead and cleaned them before I put it back in, until I can get some new plugs. I'm guess now I'll add some STP and some more clean 91 Octane gas and I think that should clear it up after a tank or two. New plugs ought to help it out too.

Does that sound about right to ya'll

STOP ! STOP ! STOP ! STOP ! STOP ! !!!!!!!!!!!
Before you add STP, you need to know that you are going to do more harm than good. STP in your fuel, CAN & COULD burn up your engine...........

And No I didn't run it before I bought it.

I know... I should have, but I was in a hurry to get back home and pick up my daughter from school.

I sure wish I would have test drove it first now.

Really Mike???

Glad you said somethin'... I haven't added it yet.

John,

Glad to hear you are making progress. First off, I would remove all of the old gas and get rid of it. If you can get the tank out and clean it - all the better. Don't try to run the old gas. Then I would add fresh regular gas and a can of seafoam. Premium gas is not buying you anything. You might want to consider pre-mixing the oil until you are certain the oil injection system is working.

You should also do a compression check. Let us know what you find and we can go from there.

Ron

Ok... so I'll pick up some sea foam and add that. I also need to pick up some oil for it, only have about a quarter left in the tank. what kind should I use?

For pre-mixing, just use any TC-W3 certified 2 cycle oil. Do you have a compression gauge?

Nah... No compression gauge.

will i need one?

John
the reason why they are asking about compression gauge is they the techs on here want to know the reading you are getting in each of your cylinders that will tell them alot right there.You can get ya a gauge at auto zone pep boys any parts house for around 30 to 50 bucks.

Mavs

I would get one. They are only about $15 or $20 and are worth their weight in gold when you are trouble shooting an outboard motor.

i would just siphon the old gas completely out first instead of just trying to sweeten up the old gas!

I think I'm going to run it out to waxahachie lake real quick and see if the carb and plug cleaning cleared up the problem.

keep us posted.....and stay off of my pet fishys out there!!!

Did you vent your gas tank?

Go to harbor freight if theres one around you they have them for under $10 and worth every penny

I agree with Mike Bristow. He may be able to help you out. He has done work on my Yamaha and he will treat you fair.

Hachie, man you need to listen to all of this advise you are getting. You can do a lot of harm to that engine by running it and putting additives that you are not sure of. As far as the man at the auto parts store do not pay any attention to him. You need good advise from an outboard mechanic. This could be a minor problem that could explode on you and cost you a lot of money you don't need to spend. Take it to a reputable shop and pay them a little to check it out before you ruin what you have.

A lot of good advice and none of it wrong. But I think some of the simplest things that can cause major headaches have been neglected.

I think you will find that the motor specs calls for 91 octane. Using regular can cause startability and low speed problems. Change the thermostats. If they are stuck open the motor is running too cool, especially right now, and the motor will have incomplete combustion fouling the plugs causing startability and low speed problems. My 95 Mercs have diaphragm fuel pumps. I don't know about a Johnson but if it does, rebuild it. Stretched out diaphragms once again cause startability and low speed problems. Remove the plugs and spray with DeepCreep (aersol SeaFoam) let sit overnight and take it and a spare set of plugs to the nearest lake the next day. Keep it on the trailer until you get it started and it is running smooth. It will smoke like you've never seen before. Pull it out of the water and change the plugs. Change all filters, check to see if there is one under the engine cowling. If you have a fuel/water separator without a clear bowl, bite the bullet and upgrade to that. totally eliminates the "Do I have water in my fuel", question.

A good service shop will include most of these repairs (actually preventative maintenance) in some fashion. A lot of engine problems masquerade as carb problems but sometimes the real fix in addition to a carb job is ensuring correct fuel delivery and complete combustion in the cylinders.

Just curious where you take your siphoned gas to dispose of? Do any shops provide a siphon service? If so, I wonder how much?

PLEASE take the advice these people are giving you. It will be much cheaper that you think. When you blow the power head you will not be happy when you find out it was some thing you over looked your self, and if you would have taken it to a shop a tech would have found the problem fast and cheap. When I bought my boat I took it to have a compleat check and they found things that I would have over looked my self. It saved my power head. If you don't know what you are doing let some one that knows what they are ding do the job it will save a lot of money in the long run.