1978 115hp rude idle question

[Mr.Stuart]

I've got a 78 Evinrude 115 HP and I'm noticing that it seems to load up, or maybe run rich at lower RPM's every now and then I have to open up the throttle and blow things out before I do any extended idling, or low rpm cruising.

Is this normal? Is there some adjustment or something where I might be able to lean it out a little bit?

Just a quick description of the engine, it's a low time motor, it has 150 lbs of compression across all 4 cylinders, and otherwise runs fine, but does seem to get a little temperamental when trying to start it for the first time after a few days of sitting, it almost acts like it wants to flood out, it always starts but it can be a little temperamental at times.

 

[HighTrim]

Re: 1978 115hp rude idle question

When is the last time the carbs were rebuilt?? Might be time for a bath/rebuild/adjustment.

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

I was told that the carbs were rebuilt 3 years ago, I was thinking of maybe running some carb cleaner through them as the engine is running but figured I'd check with you guys before I tried anything like that

 

[HighTrim]

Re: 1978 115hp rude idle question

I wish it were that easy, especially for me since i have 3 to take off You will need to take them off, give them a bath, clean them thoroughally, paying attention to the high and low speed jets and orifices, rebuild then put back together. Running a product like seafoam or another decarboning agent through your gas after will help in the future, especially if you like to troll. The kit is cheap, the most time will be spent taking them off the motor and soaking them. This video may help if it is your first time. Do you have a manual? Gl Chris

"http://www.meegsonline.com/tmd/TMDsVideoChronicle2.wmv"

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

Yup. It’s my fist time, this motor has two carbs, so do they need to be synchronized after they are put back on the engine?

 

[HighTrim]

Re: 1978 115hp rude idle question

This is the kit that you will need:

http://www.iboats.com/mall/partfind...gd_poid=109334&gd_row=80&**********=764424828

To assure proper spark advance at all throttle settings, the carbs and timer must be synced after timer linkage has been reassembled, but it doesnt necessarily need to be done when rebuilding your carbs. There are a number of other carb adjustments such as throttle cam adjustment, throttle and choke linkage adjustment, choke solenoid adjustment, etc..., that could possibly be needed as well, this is why a manual is a must. There is always plenty of help on this forum though if you need it. Good luck, Chris

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

I was just going to look up a carb kit, thanks, I do have a manual on CD, but it's not a very good one, so I should probably come up with something better

 

[iwombat]

Re: 1978 115hp rude idle question

If it's just starting to get gummed up, try running a heavy dose of seafoam mixed with gas through it. 1-gal premix to 1 can seafoam. Run it about 15minutes. Let it sit for an hour. Run it again for 15. Let it sit for a day. Take it to the lake and run out the rest. It's the standard decarb procedure, but I've had very good luck cleaning out marginally okay carbs with that procedure too. If you haven't done it in awhile, you're overdue for a decarb anyway. You've got nothing to lose.


Edit: Forgot to mention - mix it all up in a small portable tank. Don't want to run out of fuel out on the water.

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

iwombat, I was thinking about the sea foam idea, and saw some at the auto parts store the other day and almost bought it, but thought I'd ask about it here first before I added it to the gas tank.

The boat has an 18-gallon tank in it, and I am kind of the finicky type to the point that I mix the gas and oil in a 6 gallon can, then use that to fill the boat so I know I always have the mix right.

The problem with the engine (if it can even be called a problem) is almost unnoticeable, people on the boat don't notice it, but I do, and it seems to very gradually load up like it's running a little to rich the slower you run the engine, but starting it, well that's another story, you have to cuss at it a few time, grumble some words under your breath so the kids don't hear, then it fires right up, but still have to warm up for a good 5 minute before you can leave the dock with it or it might die, (sometimes but not always)

I'm not quite sure what your saying about the fuel and the tank though, are you saying get something like a portable 6 gallon tank, and use the sea foam mix in it and run that through the engine? Or pre mix it and dump that mix into the 18-gallon tank? I'm not quite sure how much or what method I should use to go about cleaning this carb problem up.

My thought would be to get a portable 6 gallon tank, mix the gas, oil, and sea foam in that, take the boat out on the water (with the 18 gallon take full) and run the 6 gallon mix in the portable tank through the engine, the fuel hook up would be a cinch to do, but the main tank runs through some sort of filter system that looks like an oil filter off a car engine, and running it from a portable tank would be straight from the portable tank to the engine (no in-line filter)

Or am I making this way more complicated then it needs to be?

At any rate, I want to try the sea foam idea before I start tearing carbs off, and delving into uncharted waters so to speak.

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

my thought was that by using a portable tank, If I ran into trouble, I could switch back to the main tank with the pure gas oil mix by just swapping the fuel line.

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

I was just reading through some of the other threads here and saw something about cold start procedures, and it's a little different then what I do, I do it the way some guy told me to do it, so now I wonder if I have it wrong and that's half my problem in getting mine started.

Here’s what the other thread reads:
"Start with a known-good fully charged battery.
Open fuel tank vent.
Pump primer bulb until firm.
Lift hi-idle lever full up.
Hold key in (to choke) while turning it to "start".

on mine, I was told not to worry about the primer bulb, unless it's been disconnected, it shouldn’t need squeezing, so I don't pump the primer bulb.

I turn the key on, push in to chock, crank the engine with the fast idler lever all the way down until the engine fires and quits, then choke off, and slowly lift the fast idle lever until the engine starts, almost never works this way, but hey, at least I'm "trying" to do it the way the guy told me to do it.

once it's warmed up, it starts right up with no choke and the fast idle lever down, I am starting to view this outboard as somewhat temperamental

 

[ezmobee]

Re: 1978 115hp rude idle question

You definitely need to pump the primer bulb and I believe you should have your warm-up lever up all the way until it starts then slowly lower it until idle. I think it will make all the difference in your cold starts.

 

[iwombat]

Re: 1978 115hp rude idle question

With respect to the portable can. You mix the decarb concoction in there and run the motor off of it. That way you don't need to throw 18 cans of seafoam in your main tank, or wait until there's one gallon left and mix in one can. With the portable you can do it at your own convenience.

Why are you mixing in another can and pouring into your tank? Seems like a lot of bother to me. Just pour some of the oil in your main tank first and top off with the rest afterwards. If I think I need 8 gallons, I pour in oil for 6 gallons. Then, I top off the fuel and add the difference in oil afterwards. Been doing it for years that way - no problems.

 

[HighTrim]

Re: 1978 115hp rude idle question

You cold start procedure is causing you grief. If you follow these steps you will find it much easier to start, no need to swear under your breath

1. Pump primer bulb until firm
2. Raise fast idle lever
3. Turn key to ON position, not start
4. Hold key in for a count of 8 seconds
5. Turn key to START, "bumping" the key in as needed if dying

 

[iwombat]

Re: 1978 115hp rude idle question

that 8 seconds isn't going to do squat for a solenoid controlled choke plate.

 

[HighTrim]

Re: 1978 115hp rude idle question

duh, thats what i get for jumping to the end of the thread

 

[iwombat]

Re: 1978 115hp rude idle question

Y'know I've NEVER done that.

 

[Mr.Stuart]

Re: 1978 115hp rude idle question

I was just going to ask what good it does to hold the key in for 8 seconds, I assumed that pushing it in, closed the carb choke plate, and releasing the key (ie: not pushing it in, opens the choke plate because it is a solenoid controlled choke from the ignition switch.

On to the fuel tank question that iwombat brought up, my plan is to use a small portable tank, put a gallon of fuel oil mix in it, and ad a can of seafoam, then run that gallon through the engine and see if it clears up the problem, run it for 15 minutes (on fast idle? or low idle?) let it sit for an hour, run it again for 15 minutes, then take it to the river, run the rest of the seafoam treated gallon through it, then switch to the main 18 gallon tank with the normal fuel/oil mix in it, and see if it runs better.

Have I got that right? And when doing the two 15 minute runs, I'll do that in the driveway, but should it be fast idle, low idle or a combination of both? or does it matter?

 

[iwombat]

Re: 1978 115hp rude idle question

You've got it right. In the driveway let it run at 1k - 1.5k and cycle up and down. (Never let it go past 2k). Give the seafoam a chance to get into all the idle passages. Then shut it down and let it do its work for awhile. Blow it wide open on the water.

It'll smoke like a house on fire. Fear not.

 

[HighTrim]

Re: 1978 115hp rude idle question

Just to mention too if this is your first decarb, it'll smoke like a chimney like IW said, and drip goo all over the ground, might wanna do it later at night. Also, the plugs will need to be replaced after, so If you have spares or held onto your old ones, might wanna put them in. Some ppl seem to get away with not, but Ive seen many threads on here about spoiled plugs after a decarb.