Rough idle, rough run, clunking jerking, violently dies and out of ideas.

[auro2tango]

First time poster, but long time reader. There hasn't been one issue with my outboard I haven't been able to troubleshoot and repair with the wonderful information on this site. But sadly I have to ask a technical question. The Engine is 1994 Force 50hp 2 stroke, 0E081281. Started giving me some very nerve-racking troubles last night. in a neutral idle I can't get it to stay idled under 2000 rpms and it makes this random jerking with a clunk ( Honestly, it sounds like she's trying to shift into gear is the best way I can describe it). When I do put her into gear the rpms drop (as expected) but the jerk and clunk are still there. The clunk and jerk are in all gears (F N R) Anything under 2000 it will idle very rough then die and in gear, you can forget about it, I assume under a load she would just die even quicker. I checked my static timing at WOT, it's right on, Changed the spark plugs and wires, double checked all electrical connections, played with the idle mixture on the carb and idle control screw on the tower. Compression is great, and starting fluid around the powerhead and carb reveal no leaks. I haven't taken apart the lower unit yet, but I like to work from the top-down and I have run out of ideas.

 

[jerryjerry05]

Sounds like the carb, low speed jet is dirty/ clogged?
​Check the reeds while you have the carb off.
Check for water in the fuel.
​Change the filter.

 

[auro2tango]

Wow, that was fast. Well in the years i have had her shes never had a carb teardown. Guess its do. Thats a fresh breath of relief, I was worried it was the flywheel key, but i assume the timing even in a tank would not hold zero at WOT.

 

[auro2tango]

No Title

Before I ripped off my carb, I took several pics researched, studied the carb.. My needles plastic tip was in pieces, the previous owner used a plastic washer from sheet metal nails for an internal fibre washer. . . Odd, but held out for a good while. Lol. Now, I noticed, that fuel shoots out of the hole pictured and that can't be normal. I ordered a rebuild kit, and wondered if there is an oring that goes in the second picture or if I need a new carb. And I mean fuel shoots out of this hole.

 

[auro2tango]

No Title

For fun, the washer. . . It's not even an odd sized fibre washer you can get the correct washer at the home Depot... Smh

 

[auro2tango]

My pics won't post?

 

[jerryjerry05]

You rebuild kit should have the gaskets/seals.
The carb uses 2
1 inside and 1 outside.
Find a parts diagram.boatsdotnet
​Most are set up the same.

 

[pete j]

When fuel shot out of that hole on my carb it was because the needle did not seat correctly and it was the needle that hangs on the float, Maybe the tip on your needle that shuts off fuel flow when carb is full is shot?

 

[auro2tango]

yes the carb needles plastic tip, if thats what the material is, was gone. My Reed valves looked beautiful. Im going to try and start the engine this evening when I get back from work. From post stalking I see trigger wires are another popular place for malfunctions, so i will check those as well. Also when I checked my static timing at WOT and my timing light set to 32 the fly marks and timing sticker line up on 0, but I see quite a few posts where other boaters are setting between an interval of 28-34. So I am a little concerned I have the wrong timing set up...now. ...? Also, I am going to get starter fluid and check for vacuum. As far as i can tell, you spray starter fluid around the base of the engine and let the vapors gradually find the vacuum? Thanks again for all the guidance. I think this forum is better than my shop manual. The manual pretty good at specs replacement procedures but doesn't really give you the years of outboard tech and troubleshooting experience that real humans have.

 

[jerryjerry05]

Timing???
​IF??? you haven't touched it??
Then it probably isn't the problem.
Check the plastic connectors on the linkage.

These outboards don't "jump" timing like a car motor.

So if you haven't tinkered with it?? DON"T!!!

 

[auro2tango]

ok reaching out again. I replaced all fuel lines and fuel filter, plugs and wires, rebuilt the fuel pump, rebuilt the carb, the plastic connector on the tower was split down the middle so i fabricated one, better than the factory plastic, its a resin impregnated polymer that i picted up at work. Machines like plastic but tougher than a coffin nail. Also its everything proof except for bullets ( I may Have tried once or 10 times). Also since that plastic linkage part was broken I set my timing light to 32 and at WOT, in gear, had all the O's lined up. I have to pick up some starter fluid to test the gaskets but with the subtle backfire and lean sneeze, Im no marine mech warrior, but if it was a car, I would speculate an intake manifold gasket. . . But with outboard 2 strokes it could be the exhaust gasket. . . Maybe?

 

[auro2tango]

i no doubt have the terms wrong, but maybe the head gasket. If its even called a head on an outboard. Also all the wiring checks out nicely, everything is grounded good clean connections. I also have a lot of schmoo (gas, oil, dirt, slime) in the lower cowl. . . Gotta be the head gasket? What would the symptoms of a blown thermostat be? There is a clicking that sounds electrical and its rhythmic and constant, that is coming from the head area.

 

[jerryjerry05]

The subtle backfire: could be the carb is too lean?
Set the air screw at 1 1/2 turn out.
Still sneezing? then out 1/2 turn more.
The adjust in the water.
The air screw: start at 1 1/2 turn out.
Motor warm, in the water.


Slowly turn the air screw in 1/8th a turn at a time.
​Wait 10 seconds between turns.(burns the fuel at the old setting).
​No changes? in another 1/8th.
Wait 10.
​Do this until it stumbles, kicks, backfires or stalls.
Then out 1/2 turn.
​Too far in can cause engine failure.,

​Misfire. Can of starting fluid, start motor and spray the SF at the base of the intake,
the base of the fuel pump and anywhere along the intake side.
​If it makes any difference in the running? then your sucking air somewhere.

 

[auro2tango]

Well, I suspect i have vacuum leaks all over the place, the very bottom of the head and the lower bow end of the port cover maybe behind the fuel pump. The starting fluid choked her out, I thought it was going to rev it up. Which was kind of neat. So i guess im buying a gasket kit, unless someone has a complete gasket kit for a 94 force 40 that they would be willing to donate a complete gasket kit. . . and anyone have any advise they would like to share in regards to a complete powerhead gasket swap? Ive done cars, dirt bikes, lawnmowers, 4 wheelers. And there are always secrets not covered in manuals. While I am in the meat of her what else should i replace look for inspect. This will be my first outboard. . . Im scared. Hold me.

 

[jerryjerry05]

My #1 thing: don't take the exhaust cover and plate off, unless you really need to.
The block has to be absolutely clean and dry to install the gaskets.
I use sealer on almost all the intake side plate seals.
​About the only one I don't seal is the carb gasket.
Maybe start a new thread on the rebuild.