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Trouble shooting 1980 Evinrude v4 140 bottom cylinders dead, poor idle, maybe crankshaft seals bad??

J

JIMTMCDANIELS

Member
Hi mates!

Any expertise greatly appreciated here:
I am use to 4 cycle car engines.

My first boat, an always freshwater glass 1982 Sprite 17" seahawk bowrider? has a 1980 Evinrude V4 140 Crossflow outboard, 1200 hours on the clock and previous owner said it ran ok before he parked it 6 years ago.

I put in a 12V new deep cycle battery fully charged and a new fuel pump(that shows no indication of leaking into the cylinder that pulse powers it).

With water muffs, it still does not idle well or for too long, warming up does not seem to make much of a difference, I need to fix this before going on the water.
The key push in primer seems to be working fine to help start it when needed.
With the warm up lever up, the rpm's hold fairly study around 2,000.
When the warm up lever is finally brought down, with the rpm's then around 700, the rpm needle surges up and down by about 500 rpm's, Although for a short period it did idle without surging..

While idling, I have disconnected and reconnected each cylinder spark plug wire and found that the rpm does not seem to be effected when removing either of the bottom spark plug wires, but either of the top cylinder wires removal kills the engine..

Also I find while idling, that there is low or no suction noticed when placing my hand over the bottom carburetor throat with the access cover removed, compared to the top carb throat and spraying carb cleaner into the bottom carb throat while idling does not have much effect.

I have replaced all the dried recirc system vacuum hoses and tested the 4 recirculation check valves using a syringe of rubbing alcohol as described in my repair manual and they test good, not allowing flow in but allowing flow out.

I have added an inline-see-through plastic bulb spark-test checker between the spark plug and the plug wire, to each of the spark plugs and they all show sparking while idling.

I have checked the compression on all 4 cylinders is 100psi and have removed and cleaned the water cooled exhaust plate with new gaskets, which only had some carbon buildup and viewed the piston tops and cylinder wall and rings are free and all looks great including still slightly visible factory cylinder cross hatch marks.
New thermostats and popetts and gaskets and short hoses installed.

I also removed the 2 carburetors and disassembled including jet orifice cover screws but did not remove orifices and found gas in the bowls, floats level, needle valves hold when mouth blowing through fuel line to and no carb gunk present and sprayed all holes with carb cleaner including low speed jets orifices and all seemed to spray through and I reassembled.
Visually inspected reeds with carbs removed, they appear good and I lightly touched them and they open with a oil sticky pop. I have ordered carb rebuild kits which include new needle valves.

I had removed all the spark plugs and turned the flywheel clock wise slowly with a wrench while holding up to my ear, a short hose inserted into the intake manifold throats and I find the top throats make a reed opening popping should but the bottom throats make no noise or a weak scratchy sound..
I don't notice much or any crankcase pressure resistance on the wrench while turning..

I have also replaced the spark plugs and water pump impeller and seals and changed the lower end oil and lower end top seals.

SO...advice please, seems to me from doing much reading that the bottom crankshaft seals may be bad/leaking-the problem?
I don't see much mention of these seals getting much focus in forums but I saw someone said they should be replaced every 5 years..

So I ordered the top/bottom seals kit (2 seals and 4 large O rings).
I see it said that the power head has to be removed for the bottom seal replacement.....does not sound like fun. and my manual does not go into detail on how to remove it.

But if there is no suction from the lower cylinders, how is the fuel pump being powered and if the lower crankshaft seal is bad, would this effect both lower cylinders or just one?

Seems I need to also remove the intake manifold and reed boxes and inspect them closer and replace the intake seal if it might be old or leaking, could cause no suction..

I have not checked adjusted the ignition timing sync as this requires to be on the water and assume that is still ok.

Any input is appreciated!
Thank-you for your time.

Jim
 
JIMTMCDANIELS said:
Thanks I was wondering about that! I'll pull the bypass plate and reed boxes and inspect today.
Click to expand...
----

Thanks guys, I have removed the reed boxes and found the bottom cylinder reeds intact BUT both have one reed cage with a small chip in the casting at the tip of where the reed curve sits causing a beam of light to pass through and definitely an air leak.
Now I have bought 4 used reed and boxes for $45 on ebay and will only need 2, but also ordered new CCMS 6500 rpm max Sport version composition reeds to install as they claim to get better idle, fuel economy and durable and won't cause engine damage if they break and I don't suppose they will chip the cage like the factory originals did.

The cylinder walls look to be in alright condition, I see some vague lines but no crazy scoring.

In the mean time, I have pulled the flywheel and am replacing the top crankshaft. The new new is definitely tighter and I had to clean and polish where the seal rides had some material from the old seal on it.
I am contemplating the bottom crankshaft seal as the seals were a kit but I'm not looking forward to removing the engine to get to it.......
My manual really doesn't say how to...


 
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Thanks for the input!
I did get it idling much better and had a good run on the Lake. Now I'm looking forward getting through the rest of this year, my mother passed away in June.
Looking forward to next summer boating and getting more friends to go and figure out any secrets of the Lake and what we enjoy to do there.

I found my Main problem were the new spark plug wires with the spark plug end machine crimped and the coil end with a boot and spring that you assemble yourself, that came with the new e-bay "Sierra International" ignition coils I got to replace the original coils which really needed new plug wires and also had chips in their casing.
Even though the metal ends were all connected to the wires, I rechecked several times and good ohm meter reading, the electricity was erradically leaking out so not sparking the plugs.
It was very random where I'd have one cylinder not producing a drop in rpm at idle when using the hook on a wooden hammer to pull off the wire from the plug. Then it'd be a different cylinder or even two the next time I tried after fiddling.
So I bought on E-bay new "Marine Pro" 9" plug wires that already have machine crimped ends that appear to have superior insulation for the wiring.
Now all cylinders are firing well at idle so the rpm's are much higher although my idle screw must be turned all the way in, which of course increases the timing, set with the carbs not opening till the throttle is advanced from there.
The high idle screw setting I suppose may have to do with my altitude of 6,000 ft or another problem I have not solved.
Another problem I found is even warmed up, it seemed the high altitude idle jets were too lean as the rpm's would increase with spraying gas/oil mixture into the carb throats. So I put the original smaller(they let in less air) top jets and it seemed much better.
I did leave in the high altitude high speed jets and noticed when being pulled behind the boat, the fumes are much less than before.

Although I have another problem to figure out next year, seems it may be a fuel restriction the internet seems to say to check lines and filters although my lines and filters are new lol, in the water towards the end of the day, at full throttle, if I push past say 3,000 rpms, it would get to 4-5k and then the engine would die all the way down to have to restart. Even if I pulled back on the throttle. It would restart fine. Also after sitting with the engine off for say 30 min, the idle would be low without the warm up lever up and it seemed to take a while to get to where the idle was "warmed up". The water temp was 69 deg.

Anyhow thanks for your help guys
 
The easiest way for me i just change the firing order around at the power pack if the problem shifts to no1 and 2 cylinder at the moment you have 1,2,3,4 firing order make it 4,3,2,1 then you have either a powerpack problem which you need a DVA meter for to check if its producing volts or you have sensor problems in the trigger
 
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