Evinrude 6HP 2- cycle question

[a64pilot]

Originally Posted by skipgundlach

I wonder if the bug from MX is the same as we knew as kids, or some other incarnation with the same body/frame, etc...

Sorry, I meant have you driven an older Bug recently, seems we don't remember their shortcomings as we were younger and less reliant on things like airconditioning then.
Sorry I can't think of anything water cooled and front engine as a Bug, they just aren't. Like the new BMW mini's, they aren't Mini Coopers to me either.
I'm not sure the Bug is still manufactured in Mexico, but when it was, it was very close to the old Bugs.
Of course even among them there were several variations, the Super Bug was actually very different from an old Bug, from the suspension to the disk brakes and much more powerful engine, even a larger car.
Apparently the Bug died in Mexico in 2003?
https://en.wikipedia.org/wiki/Volksw...etle_in_Mexico
I'm bad about thread drift, but it keeps the thread alive.

One thing often missing, when the problem is resolved, often it's not posted, so the rest of us don't get to learn.
I'm hoping the rattle is just too rich a mixture messing with ignition, not a bottom end (crankshaft) problem, never heard rings cause a rattle myself

[skipgundlach]

Originally Posted by Cadence

How old is the engine? I've had what sounds like similar problems with two older OMC's 9.9s.
They would not hold a point gap because of an worn upper main bearing. Had it with a 3Hp from a coil arcing to the underside of the fly wheel.


Ancient history but OBs of that size seem to stay around forever.

The plot thickens.

When I bought the lightly used engine, the dealer who took it in trade didn't have the correct manual for it, so gave me a 2005 version.

It specifies 50-1, so I have no idea what caused the discussion about 100-1, as the manual is for a 5 years later model, but any such fuel has long left the engine, as I may NEVER have run it that way, as it could run on 50, and even recommended 25-1 for heavy or racing type use. So, I'm reasonably sure we don't have a fouling issue due to too much oil. The engine type shows that it matches my hood, which says Johnson on it, J6RSSM, a 2000 Johnson 6HP, recoil start, with the last M escaping me. Why I thought I had one each J and E engine, I can't imagine - but they work the same, so it's no issue other than to slap me upside the head

My first test was to take my spare plug wire and substitute out for each one. Along the way I discovered two potential issues.

First was that the lower plug's coil spot was a bit corroded. I'll hit that with some crocus cloth and corrosion-block all the connections points.

Second was that the first plug at the coil end appeared to be not fully seated.

In the end, I'd swapped out both plug wires and run in neutral; removing one plug wire made it nearly impossible to run. Slight improvements every time I made a wire change.

So, I took off the spare, and made sure that both originals were well seated (and improved the run of one of these 3-4" cables). Idling much improved, and some improvement with only me up, WOT.

Perhaps some running with a better ignition will clean out and improve the running as more fuel goes through it. In the meantime, I'll pull the cover again (a bit of a nuisance due to our hoist handle we also have to remove and reset, a several step process) and burnish and protect the connection points.

L8R

Skip

Morgan 461 #2
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[mowerandy]

I have a new Chinese motor (Hyfong 6hp) which seems to do the same - 4-stroking and only developing around 3HP tops. The book says it is supposed to run on 25:1 like a lawnmower or something (but no outboard I have ever owned previously). I decided to run it in on 25:1 then go 50:1 after that. This seems to have helped a good deal but it still seems not to get near its full 6HP rating (or run anything like in the clips and commentary I have seen of them on youtube). I reckon the air/fuel mix is rich, like with the choke still on when its not, but haven't had opportunity to investigate further...

[GrahamHO]

Originally Posted by Stu Jackson

Skip, more info is always helpful.

On my 1971 VW Super Beetle - loved that car ex-wife made me sold it shoulda sold ex-wife first! - it turned out rough running was because the spark plug wires needed to be replaced.

Good luck.

In my '56 VW I dropped the engine out the bottom, pulled the heads off and the exhaust valves had a buildup of carbon that caused the valves to be almost closed again when they opened. I have also found carbon build up on the cylinder exhaust ports of 2 stroke motorbike engines.


I had a Honda outboard and the HT lead plug (that attaches to the spark plug) had a suppressor built in. That had open circuited. I cut the end off and substituted a standard auto type plug and it ran like new again.




It sounds as though it's a 2 cylinder motor you are describing so I think you are correct that the carb would affect both cylinders.


Usually 4 stroking is a rich mixture but not necessarily. Try running it with one plug lead removed at a time to find out which cylinder is playing up.
Then try swapping the plugs around to see if you get the same result.


I imagine the plug leads are one piece with the coil so it would be expensive to change that. If all else fails and the leads have enough length you could change the HT plugs on the ends of the leads to an automobile type. Doing that fixed my Honda after all the usual things made no difference.

[skipgundlach]

Plug leads are typical. Post on coil output is typical to automotive distributors. One of coil posts has some corrosion. The engine will nearly not run on one cylinder - either one; I'm sure it's not a failure of one cylinder's ignition.

It's back together so it's a nuisance to get to (Davis lifting system) but soon I will crocus cloth the posts on the distributor, and if I can get the ends out of the boots, burnish those as well. Both ends of both leads will get corrosion protection as well.

L8R

Skip

[GrahamHO]

You could also try running it flat out on the dinghy with enough sea room. Keep the throttle wide open for as long as possible and it may gradually start running properly. When it was new my 5 HP Mercury would 4 stroke at gentle speeds but clear after a hard run. For some reason it fixed itself eventually.

[GrahamHO]

Originally Posted by skipgundlach

Plug leads are typical. Post on coil output is typical to automotive distributors. One of coil posts has some corrosion. The engine will nearly not run on one cylinder - either one; I'm sure it's not a failure of one cylinder's ignition.

It's back together so it's a nuisance to get to (Davis lifting system) but soon I will crocus cloth the posts on the distributor, and if I can get the ends out of the boots, burnish those as well. Both ends of both leads will get corrosion protection as well.

L8R

Skip

After burnishing the electrical connections you could apply some contact spray from an electronics shop. Then you can use clear silicon out of a tube to waterproof the insulated HT lead connections. Not on the metal contacts of course. Probably what you are intending to do.

[skipgundlach]

So, I get the thing apart for the 4th or 5th time, and I'm helping a fellow cruiser figure out HIS poor-running engine. In the process, I'd brought along some emery cloth.

I burnished the coil posts - but noticed that that end of the spark plug wire was actually rusty.

Burnishing helped, but I ran back to our boat and grabbed the spare wire and went back to continue with him. Then I swapped out the rusty-ended one for my spare, which looked fine. All connections were also WD-40'd (what he had on hand). The spare swap and the burnishing(s) made a small improvement, each, but it's still not humming yet.

So, he'd bought some carb cleaner in town, but his is injectors. I swapped him sea foam (his sounds like maybe either one or more of the coils [he has 3] or plug wires, as it idles perfectly but fails under load for the carb cleaner, my {other} reason for my return to the boat), making sure this thread doesn't go off the rails into a discussion of his motor and injectors vs carbs

But my owner's manual, and, so far, all of my googling (remember I'm in the Bahamas, so it's not like most of you have) fails to turn up how to either rebuild/clean (besides putting in an ultrasonic bath) the carb, or, worse, how to get to the damn thing. The air cleaner has no discernible (well, not to me) means of opening, and the only way I can see to get to the carb involves taking off the recoil mechanism in order to get to the screw which holds what I presume to be the air cleaner.

Surely someone here has had their 2000 era 6HP carb in full view...

So, how do I spritz carb cleaner into this while it's running, before I risk losing parts overboard to do a full disassembly/cleanout?

And does anyone have some sort of visual (not YouTube - I don't have the bandwidth) illustration of what I have to look for if I take it off? I've rebuilt carbs so am not the least bit intimidated but don't want to miss something.

Thanks.

L8R

Skip

Morgan 461 #2
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[GrahamHO]

In my humble opinion carb cleaner in the intake shouldn't be necessary.
It won't clean any debris out of the float bowl. A hard run at full throttle will do the same as carb cleaner in the intake. My Mercury 5 can optionally run on high octane gas. I use BP 98 as their propaganda suggests it has excellent cleaning properties. (as I understand octane numbers are a different type of rating system in the U.S.) The extra cost isn't much on a 5 HP. Higher octane of any make has more additives which are better than the snake oil stuff you can add.
You may be having trouble with dirty gas in some places. I've had trouble with notoriously dirty gas in a rental car in Western Samoa.

[skipgundlach]

Originally Posted by GrahamHO

In my humble opinion carb cleaner in the intake shouldn't be necessary.
It won't clean any debris out of the float bowl. A hard run at full throttle will do the same as carb cleaner in the intake. My Mercury 5 can optionally run on high octane gas. I use BP 98 as their propaganda suggests it has excellent cleaning properties. (as I understand octane numbers are a different type of rating system in the U.S.) The extra cost isn't much on a 5 HP. Higher octane of any make has more additives which are better than the snake oil stuff you can add.
You may be having trouble with dirty gas in some places. I've had trouble with notoriously dirty gas in a rental car in Western Samoa.

Thanks. So, do I have to take the recoil starter off to get to the carb? As above I see no way to access the throat, let alone get it off, without...

[Cadence]

Have you run it cowl off in the darkest of night? It may show some arcing or corona coming off the high tension leads?

[skipgundlach]

Good thought, though I've not.

I used to have a Fiero which did something of the sort, and I could HEAR the tick...

[GrahamHO]

Originally Posted by Cadence

Have you run it cowl off in the darkest of night? It may show some arcing or corona coming off the high tension leads?

That reminds me of a problem I once had on an outboard. Unknown to me the exhaust bend had a corrosion leak. I'd fiddle with the motor and get it going and put the cowling back on and it wouldn't run very well at all.

My then 10 year old daughter remarked that it only happens when the cowl is back on. I said that the cowl can't make any difference.

I was wrong! The motor was breathing in its own fumes and snuffing out.

The same can happen with closed in outboards in wells.

I made a new exhaust bend out of SS with the help of a friendly welder and fixed the problem.

[GrahamHO]

Originally Posted by skipgundlach

Thanks. So, do I have to take the recoil starter off to get to the carb? As above I see no way to access the throat, let alone get it off, without...

Sorry I don't know the details of that motor. Someone put it together so it must come apart. Take the fuel tank off first if it's got an integral one.

[skipgundlach]

External tank only...