'62 Johnson 5.5hp Difficult Cold Starting

[OptsyEagle]

Well, there has to be something that you currently think is correct, that is not correct. You have OK compression, you have good spark, it is timed well from your point gap and spark plug wires going to the right cylinders and you have manually put fuel into the cylinder holes and it will not start. Even with crankcase seal breaches I would think it would pop with fuel put directly into the cylinders.

I would start at the beginning and go back and test the compression, spark and perhaps for a quick test, try a different fuel into the spark plug holes. Pull the spark plugs and rip on the cord a few times to make sure any residual fuel is out of there and not causing a flooding condition. I sometimes use seafoam to quickstart it. It is combustible and has a small amount of lubricant. I would even switch the spark plug wires just to be sure. Not to keep harping on that one but your problem is beginning to be quite the mystery. From what you say is correct, the laws of physics says that your motor should be purring like a kitten.

 

[OptsyEagle]

One more thing. What about a sheered flywheel key?

If the above all checks out your next step would be pulling the flywheel again to re-check those point gaps, so give that key a good inspection as well.

 

[racerone]

If the key is sheared there will be no spark.---On electronic ignition engines you would still have spark but at the wrong time.

 

[HighTrim]

If it was someone that hasn't worked on a lot of these, I would say revisit the points.

In your case, I am sticking with a crankcase leak. (Sorry, not an easy fix, but what Im thunking)

 

[oldboat1]

Thinking a leaking reed valve might produce an overly rich mix, which could explain the need for that super lean setting -- engine could really be starved for air. Throttle increase could stall it out (essentially flooding it), and the problem might not be readily detected with a compression check. Additionally, squirting fuel into the cylinders would probably not increase chance of firing -- in fact might increase chance of flooding.

Symptoms as I see it appear to fit -- similar effects to the crankcase leak HighTrim discusses, I think.

Alternatively, it's possible the h.s. needle isn't fully seating (washers blocking, maybe), and the needle is actually being set richer than it seems -- worth rechecking the needle fit and setting, as that's easy. Maybe test seat it without washers to make sure it's bottomed out.

(Stuff you probably considered, Lindy. Motor seems to have had operating problems for a while -- idle speed issues and finally a busted needle, J8 plugs. Think its got a secret.)

 

[lindy46]

Thinking a leaking reed valve might produce an overly rich mix, which could explain the need for that super lean setting -- engine could really be starved for air. Throttle increase could stall it out (essentially flooding it), and the problem might not be readily detected with a compression check. Additionally, squirting fuel into the cylinders would probably not increase chance of firing -- in fact might increase chance of flooding.

I think this is worth checking. Seems to me too that it just isn't getting enough air. I just pulled the cold motor over a few times (it didn't start as usual) and checked the plugs - they were quite wet. Maybe the reason previous owner put in the hotter plugs. Checking reeds is a good place to start and alot easier than tearing into the crankcase (which ultimately may be the problem area). I really don't want to do that and I know the customer doesn't want to sink alot of money into the motor. They initially only wanted me to check over the motor and clean/rebuild the carb. I'm sure glad they aren't all this challenging.

 

[oldboat1]

Yeah, might have a blockage in the exhaust housing too, way up in the leg. I had one like that (mouse nest), and found it pretty much as a last resort. (Similar operating symptoms.)

not sure what the best choices are, cost-wise -- reed valves, check for blockages under the exhaust cover or up in the leg? Hobby time is different. (Maybe the customer will spring for water pump work, and you can check for blockages in the process. Can be particularly thorough if the powerhead has to come off, as I think it would with that one.) Reed valve troubleshooting is what it is, I guess.

 

[HighTrim]

Reeds are easy enough to check, as is pulling the exhaust cover and having a look for a blockage. Hopefully anyways

 

[geoffwga1]

I know this is pretty obvious but have you checked the needle packings?

 

[lindy46]

Well, I now own the 5.5hp Johnson. The customer didn't want to put any money into it, so she gave me the motor in exchange for my time already spent. Apparently she got it with a boat she wanted (and bought) and the seller threw this motor in with the deal (what does that tell you??). So she paid nothing for the motor. Now I can take my time and play with it. First I'll pull the intake manifold and check the reeds, and then move on from there if necessary. Thanks all for your suggestions. I'll keep you informed of progress.

 

[racerone]

Someone will have to explain how a leaking reed valve would cause an overly rich mixture.

 

[oldboat1]

On the intake stroke, a partial vacuum is created pulling air and fuel in through the carb and reeds. Leaking valves allow more fuel/air mix to be drawn in, but finally the volume of fuel overwhelms. Unless the excess fuel somehow is burned, the leaking reed(s) invite more flooding. Starting can be particularly problematic because the the volume of fuel continues to increase unless ignition occurs early in the starting process (at an early point before flooding). A contributing factor is that air for combustion is leaked back into the crankcase, leaving heavier unburned fuel to continue the flooding process -- even if some of the air is returned from the crankcase with additional fuel. In other words, the volume of air doesn't increase in proportion to the volume of fuel. That is a flooding condition: the fuel/air mix in the cylinders gets richer. A leaking reed is arguably worse than a broken one, because the effect is more subtle (may be no popping through the carb or spitting back fuel).

 

[racerone]

????--Leaking valves allow more fuel/ air mix to be drawn in.---Are you 100% sure that is what happens and how would you explain how that happens.

 

[HighTrim]

While I do not want to get in on the debate regarding whether faulty reed valves would cause an over rich condition or not, what I think we can all agree on is that hard starting, backfiring, blowing crank seals out, damaging recirc valves and hoses, etc.... are all symptoms of faulty reed valves. So, having faulty reeds COULD cause a hard start condition that Lindy is experiencing, Im not really convinced that is the case here though. Just my 2 cents.

1. I almost never personally find a fault with this vintage of OMC reed. I can only think of 1 motor out of say the last 100 that Ive tuned that had a reed problem. That was an easy one, it broke right off, and was spitting out the carb throat. 99 times out of 100 though, they are just fine.

2. I believe, and underline believe, that introducing a fuel/oil mix directly into the cylinder should get it to pop more than it is, even with a faulty reed valve.

Im still stuck on lost crank case compression, or possibly plugged exhaust.

I hope you lick it. Curious here.

 

[racerone]

Agreed a faulty reed valve ( even a missing reed ) does not affect compression in the cylinder !---The motor should fire with ease.

 

[HighTrim]

Agreed a faulty reed valve ( even a missing reed ) does not affect compression in the cylinder !---The motor should fire with ease.

Yup!

Old boat.....I am by no means an expert, but not certain that is the way it is. I believe the main jet will only allow a certain amount of atomized fuel/air mix to be drawn in.....broken reeds or not. I don't think that broken reeds would allow more fuel/air mix to be drawn in. I am thinking that like a leaking intake manifold gasket, or leaking crank seal, or faulty spaghetti seal, a faulty reed would only contribute to a lean condition, eventually causing piston failure, if run at excessive WOT high rpms.

I am certain that a lot of our older motors have more of an air leak than we would imagine. I know I for one do not pressurize crankcases like the high revving racers do. An air leak for them is catastrophic, while in our recreational outboards, it can be less damaging. Initially anyways.

Racerone, I would imagine that one of these crankcases should be able to hole about 6 to 9 psi or so for 10 or so minutes no? What do you think?

 

[racerone]

Not a chance of the crankcase will hold pressure for 10 minutes.---There are just too many small leak points !

 

[oldboat1]

Will watch (curious). Interesting info.

 

[lindy46]

Well, I had some time to pull the intake manifold and check the reeds. They looked fine. I took the opportunity to clean things up - did find some sand in one of the pockets and cleaned that out. Cleaned out the small orifices with a wire, and sprayed carb cleaner in them. The manifold incorporates the sediment bowl into it, and with the manifold off, I noticed the "in" and "out" markings underneath the fuel line connections. These are really difficult to see with the manifold mounted on the motor. Well, anyway, the lines were connected backwards. Switched them around and now the motor starts cold with about 10 pulls (better!). I choke it for the first 3 pulls, then open the choke and she finally sputters around 8 pulls and then starts a couple pulls later with no further choking. Once warmed up, she will re-start on the first pull, and purrs like a kitten. So I've made some progress. I'd still like to see her start cold with 2 or 3 pulls.

 

[oldboat1]

hey -- glad to hear about progress. Are you thinking some unfiltered tank sediment got through to the carb and the intake? Think your motor has a bleeder pocket, and sounds like some stuff might have ended up there, however it got there -- and wasn't blown out into the exhaust passage. Even if the reed on the bleeder valve is working right, maybe exhaust pressure isn't enough.

But guessing some blocked venting might have contributed to the cold starting issues before you cleaned up the passages (I keep thinking of a rich condition). Others might infer a lean condition there, or no effect -- not sure.

Any other evidence of stuff in the system? Under exhaust cover, maybe. Suppose it's possible the motor was dunked at some point. Think you may have said compression and cylinder condition is OK. Maybe just letting her run for a good long time will finally clean her out.

(Have some similar symptoms on one that sat tucked back on the stern of my boat most of the summer, so some selfish interest in watching you fix yours. Can't get at mine to work on it yet. Screwed up Fall fishing a little -- thinking some mud daubers, or similar. Should have done more fishing.)