Old Evinrude running rough?

Larryrsf

Larryrsf

Member
With zero experience, I wonder whether my old 1979 Evinrude 150 runs rougher than it ought to. It has sat idle for 14 years before I bought the motor and started it. The compression numbers were ideal! The powerhead had been rebuilt before it was sold and then stored.

We got it running. But my mechanic said ideally the carbs should be taken off and completely rebuilt, jets cleaned and floats reset, etc. That was in mid-May. He admitted that he wouldn't be able to do it for weeks, and that rebuilding the carbs would be expensive because he is swamped with work right now. I wanted to get the boat into a marina slip and use it several times a week now that it is Summer here. So it's down there.

It does function. It starts immediately and runs fine. But in order to keep it from dying when I shift from neutral to either reverse or forward, I had to set the idle pretty fast. When it shifts into gear, I get a significant clunk-- and then minimum speed is really too fast. I would love to slowly troll, but I have to shift back to neutral in order to keep it safely moving slowly between slips in my marina.

I added a fuel additive the mechanic suggested that is supposed to be cleaning the carbs and engine-- and maybe the more it runs, the better it will run.

Should I just live with this fast idle for the season?

Larry
 
I wouldn't. Dirty carbs is one of the top killers of 2 stroke outboards. When the jets are dirty, they aren't flowing fuel like htey should be, and this in turn leans the engine out which can and has burned alot of pistons. The idle problem is because it is lean. So you have to idle way up to keep it running when the load hits the engine. And if it's an air bleed, the ONLY way to clean them is to pull the carbs off. Also make sure they know what they are doing. It always shocks me to see how many people call themselves professionals at working on these old engines, but can't figure out how to line up the link and sync marks when setting the carbs up.
 
I brought an old motor back to life. The Suzuki DT200 in my signature.

I don't know anything about your particular motor, and I'm not a mechanic, but I wouldn't do anything until I pulled those carbs and THOROUGHLY cleaned them. Running seafoam or spraying carb cleaning in the throat of the cab won't cut it.

Even pulling them and spraying them out may not do it. I pulled mine and scrubbed them and scrubbed them, blew compressed air through them. I did that about 5 times. Each time they would run well for one trip and then get gummed up again.

I finally took them off and brought them to a local guy who agreed to soak them in some kind of untrasonic hot bath, and I installed rebuild kits on them. It made a HUGE world of difference.

I would do the other low hanging fruit stuff too .. replace the fuel filter and water separator (if you don't have one, install one) .. make sure you don't have any water or moisture in the tank ..

Good Luck!
Chris
 
Good post Chacket. Agree with having a clean tank with good fresh non ethanol gasoline. Will save you a bunch of trouble. Good fuel lines with fresh water separating fuel filters are a must too.
 
I have done everything listed here except having the carbs off and rebuilt. During the boat refurbishment, I removed and cleaned the fuel tanks, installed all new lines, new fuel filter/water separator, new selector valve, and replaced every rubber fuel line to and between the carbs. There are no leaks.

But the boat is in the Marina now and will be there until October or so. I doubt I could easily remove the carbs while the boat is there. And even if I did, my outboard mechanic is buried with work this Spring-- and probably couldn't do the job for weeks--and then would charge me the proverbial "arm and a leg!" So I will just have to live with the rough idle-- or slightly too fast idle to prevent it dying when shifting from neutral.

I have added the right amount of a fuel conditioner that he recommended. I will continue that, of course. He said that might slowly improve the idle as it cleans the jets.

I just realized I should be flushing the engine with fresh water after each use in sea water. So I will take the muffs and a hose to the marina and do that after I bring it in to the slip. I see the other owners keeping their outboards tilted up out of the water between uses.

Thanks for your advice!

Larry
 
Paying the proverbial arm and a leg is cheaper than having your lower unit rebuilt because you ground the clutch dogs off shifting it, or worse yet, burnt a piston and scored a cylinder wall because it leaned out. Putting it off will almost always cost you more money than to just bite bullet and fix it. It is shocking to think how many good engines I have seen burned up because of something as simple as trash in the carbs.
 
I think it is running better all the time. I had it out today for nearly 2 hours. Tomorrow I will try to adjust the idle slower and also lube up the throttle mechanisms so that it always returns fully to the idle setting stop. I suspect it has been sticking slightly open.

If it won't keep running when shifting into gear while running at the design slow idle speed, I will take action.

Right now while my trailer is being rebuilt, I have no choice but to work on my outboard engine in place, on the boat in the slip in a marina. I can't pull it out of the water and even if I did, NO mechanic will work on the carbs during this busiest time of the year for them. Lets be practical. We have only these few months of ideal weather. It would be really silly to sacrifice them while working on the boat motor.

Thanks for your advice. I know it is well-intentioned.

Larry
 
Well, there's always the old adage... "you can pay me now, or you can pay me later". While I agree it's a shame to burn days waiting for a mechanic to do the carbs, I cannot help but think.... how much additional time will be spent if you have to buy and mount a new engine? Really, I wish you luck and good fortune with your gamble. If it were me, since I simply cannot afford a new engine, I'd follow Ferm's advice. These guys know what they are talking about, they do this for a living. But maybe you'll get lucky and nothing will happen.
 
Yeah, like I didn't pay $100 for the boat, motor, and trailer!!! I didn't even want a boat until this thing fell in my lap.

I started the engine today and adjusted the idle down. It really does seem to run more smoothly all the time! I really think I am going to get by with this. The Mercury Carb cleaner stuff I am adding to the gasoline seems to be working. (My mechanic is a Merc expert).

But if it suddenly locks up and I have to be towed in, then so be it. I have the BoatUS unlimited towing insurance for both boat and trailer. I would either find a used engine or I might even buy a shop manual and overhaul the powerhead myself. I am a graduate nuclear engineer. Don't doubt that I could do it. And don't doubt that when it is finished, it would run like a watch. I love a project. This is really "not rocket science."

larry
 
It ran two hours today after starting easily. If you Google San Diego Harbor you can see where we went. We went from the Marina behind Harbor Island over to Glorietta Bay, under the bridge and up near the Hotel Del Coronado, the Coronado Yacht club basin. Most of the trip was made at 1500 rpm, about 10MPH, slowly enough that we were able to negotiate the BIG waves and wakes without scaring my wife! ha

It is running more smoothly all the time. Now it idles slowly enough that shifting is not a big clunk-- and of course it doesn't die when shifted from neutral to either forward or reverse, so I was able to deftly maneuver out of and into the slip. All good--so far! ha. My wife said I am becoming a boat handler, ha.

larry
 
You must log in or register to reply here.
Back
Top