Logo

1980 Evinrude 140hp v4 crossflow Not Running as it should - video links

Hi looking for experience/advice, I do have experience with cars and have 2 Evinrude manuals I've acquainted myself with!


I've had my 1980 Evinrude Outboard 4V 140hp crossflow 1200 hrs, on my 1982 Sea Sprite SeaHawk 16' open bow trihull for over 2 years and it's running Much better since I've been improving things, BUT still not perfect..


2 things aren't right and I'm not sure what to look into next, perhaps it's all related to one thing I've missed, I've attached 3 short videos to show the engine settings and in operation:
-
2 problems:
1. There's an intermittent clicking sound only some at idle in neutral and more so as coming back to idle in neutral, if I manually rev the engine slightly. I can only really hear with the hood off.
This slight clicking seems to go away if I temporarily disconnect the throttle cable and carb butterflies so I can manually retard or advance the timing with the butterflies closed...


2. Engine idle in gear spec is 650 rpm but sometimes it stalls in idle so I have the screw turned all the way in and it's only 800 rpm idle in gear(1200 in neutral).
Seems the idle screw should be able to increase the idle more than that. Maybe this has some to do with the 5,000 feet altitude I'm at.
The engine also sometimes stalls when re-starting after hanging out in a cove for say 45 min. Also then stumbles and dies when trying to get above idle. However if I can get it to full throttle, it runs like a raped ape just great, up to 35 mph, @ 5400 rpm.
I've followed the link and sync exactly. The timing cam picks up right at the short top mark as prescribed. At idle, the timing is already at the 5 deg btdc pickup spec.. The cam follower nylon roller has a very slight gap from the cam. So the butterfly valves just barely open all the way at full throttle with the throttle stop screw turned all the way in.
-
Perhaps:
a. this is some preignition click noise however I don't know why it would go away with advancing the timing, perhaps this means it's getting too much fuel(it does smell over gassy at times)..
b. Or maybe it's piston slap (I have a Buick that has that problem especially when cold but it's just makes it sound a bit like a diesel at first)
c. Or maybe an intermittent missing, although the coils and wires are new, although I did move my timing gun induction to the other three plug wires and the gun light flash can be intermittent on them but when I pull a plug wire completely off, the engine rpm's drop way down.
d. Or maybe the carb floats are too high and giving too much gas.
e. Hoping it's not an internal bearing and since the engine sounds great at WOT, I'm guessing that's not the case.
-
Video 1 - shows only throttle cable disconnected and engine idle in neutral with throttle manually advanced and then back to idle, clearly exhibits clicking sound coming back to idle.
https://youtu.be/6dW0G8dFwI0


Video 2 - shows only butterfly valves manually advanced, to show characteristic and sound of engine with only carb advanced.
https://youtu.be/H8Cqcu3zPBc


Video 3 - shows throttle cable and butterfly pickup disconnected, manually advancing timing advance at idle, to show characteristic and sound of engine with only timing advanced.
https://youtu.be/gQ1Xox2RVnY


PS: I'm curious, if anyone knows what the second mark "start" on the cam lobe is used for anything significant?


I'm land locked here in Colorado so I only take it to lakes.


Well thank you Greatly for any Help!




Jim
 
Those values are low.----Test with another " known to be accurate " gauge.

I think my gauge is accurate.
When I first got the boat, the compression came up in a discussion and some said the compression doesn’t matter as much as the readings being about the same and service manuals seem to say the same thing.


Is there anything to do to prevent the piston rings from breaking in the future?
If they break, do we just loose compression or does it score the cylinders?
I’ve looked at the cylinders look ok, not scored.
 
Ok guys thank you for pointing out the compressions are low.

I've done some reading and have taken the spark plugs out last nite and sprayed sea foam into around the piston edges because I've read others getting large compression improvements after doing so with such sprays.
Also I took the readings last year and I can't remember if the butterflies were opened during the cranking.

I'll test get new readings hopefully today and post them here.
 
HI!
Ok thanks everyone, the results are in!
You guys have more experience than I so
Please let me know if you think the engine is worn out and needing rebuild!

7/17/20 Compression tested COLD, cranking for 5 seconds each:

Cylinder #1=106 (*126.8) psi, 2=108(*129.2), 3=102(*122), 4=100(*119.62),

The number after the Asterisk is after I adjusted for altitude. I live here in Colo Springs at 6,000 feet here.
I looked and looked and found just a few discussions about adjusting for altitude and it makes a big difference for this altitude. The following site gives an compensating formula from a Yamaha motorcycle repair manual however it reduces the manual's called for reading(by multiplying by .836) so I reversed this to bring up my readings since we have no min psi manual values to reduce down to.
From the chart, I found my 6000 ft altitude requires the readings multiplied x 119.62%.

https://www.tw200forum.com/threads/altitude-correction-factor-table-for-compression-testing.61426/

https://kzrider.com/forum/2-engine/385711-effects-of-altitude-on-compression-readings

My gauge is old from about 1992 but rarely ever used and the first 2 cylinders I tested came up the same as above BUT then the schrader valve started leaking in the gauge hose and even though I replaced the value and it stopped leaking, the gauge was reading low in the 60's on the same cylinders.
SO I bought a new tester at Advance Auto, an Innova with great reviews and used it on all the cylinders for the above readings. The Innova manual doesn't call for altitude adjustment either, although they probably wishful-thinking expect the vehicle's service manual of the particular vehicle addressing that....


Also, what do you make of these, I found some other interesting discussions about acceptable outboard compression by googling, makes this all a bit vague and confusing:

I mean, one of the gentlemen is this discussion says he tests outboards all the time and that 80-100 psi is fine, especially tested cold:
https://answers.yahoo.com/question/index?qid=20080812160518AAbbWSq

In this whole article dedicated to checking compression, written by a master technician, and another article, generally says that 90 to 105 is normal for 2 cycles...although he does say that larger than 25hp have higher compression than the smaller engines and that high performance engines should have higher compression. I believed my 140 was high performance for it's time since it's the same displacement of some lower hp model Evinrude engines although I know it's not a high performance looper that came out in the late 1980's.
https://www.boatus.com/magazine/2016/april/checking-compression-on-an-outboard-engine.asp
https://thisoldoutboard.com/what-is-good-outboard-cylinder-compression/
"Generally, readings below 90 PSI for modern two-stroke outboards indicate a problem; most will produce cranking compression readings in the 90 to 105 PSI range, depending on the engine year, make, and model. For older models and high-performance engines, readings should usually be in the 115 to 140 PSI range, again depending on the engine make, year, and model. Four-stroke engines can produce much higher compression".

Also I found like an exact match to my engine for sale and they say it's in very good condition and that the compressions are 130psi on all 4 cylinders and they are located in St Petersburg FL and the elevation there averages 13 feet. So adjusted for altitude, doesn't it seem my compressions are almost the same but not as even?
https://www.smalloutboards.com/j14080.htm

Also, in this discussion, it's pointed out that the OMC engine compressions were dropped down for emerging unleaded gas, making 90-100psi normal when new for that transition era.

"Another good example of compression changing throughout the years would be in the OMC crossflow V-4 line. The older 115s and 135s had compression up in the 120s, 130s or higher but the later model engines designed to run on lead free low octane fuels went all the way down into the 90-100psi range."
https://tinboats.net/forum/viewtopic.php?t=20816

The internet seems to say the phase out period started in 1970 and wrapped up in about 1987. My engine is a 1980.
http://www.todayifoundout.com/index.php/2011/11/why-lead-used-to-be-added-to-gasoline/

Very Respectfully!
Jim
 
Wow Crickets

Well I discovered that the induction timing light is consistently picking up all the cylinders firing If I don't place the pickup clamp at in a 90 degree spark plug wire bend. Evidently this confuses the pickup. So my ignition system seems to be just fine.
Now I am going to take the carbs off and inspect the floats levels and an signs of the float valves leaking. Because I suspect it's getting too much gas.
 
OK I GOT HIM RUNNING GREAT!

The problems were:
1.
The cylinder heads 1/2" socket bolts were not torqued enough at all to spec. is 19 ft lbs but they were only to about 10.My manual also says to re-check/torque the bolts after running the engine to temp and cooled off again. My torque wrench is the clicking kind and the stop joint click is very subtle when on lower settings.
I noticed that just a little water would appear on the top of the engine block at the heads gasket and also some drops under the heads. Once the engine warmed up this would evaporate but seems the water was leaking into the combustion chamber causing erratic idling and more at different temps.
I also torqued the spark plug mount/plate bolts (7/6" socket) to the 70 in lbs per specs, they were about right already.
2. The in line Walmart Atwood brand fuel primer bulb was acting up and not pumping up hard even though it was only 2 years old. I found from searching the web and reading reviews, that Atwood primer bulbs are problem prone and only engine name brand bulbs should be trusted to last and bought. So I bought an evinrude bulb on ebay, works great so far.
ALSO I found from reading that the bulb Really should be mounted vertically so that they are pumped when vertical because their moving valves are aided by gravity AND if mounted vertical, this ward off the fuel from running back into the gas tank. It's nice having it mounted now so that I always grab at the same location to find and squeeze it. Pic attached.
3. I removed and thoroughly checked the 2 year old 3/8" gas fuel line hose and all connections and checked for any air leaks. I believe my fuel tank internal pick up flex tube that goes down into the gas, had a bit of an air leak at it's top attachment point which would allow the pump suction to pull in some air instead of gas. My 140 hp engine takes the 3/8" fuel line, smaller engines take 5/16" line.

Hope this helps someone with the same problems.

Take care
 

Attachments

  • IMG_0672.jpg
    IMG_0672.jpg
    93.4 KB · Views: 83
Back
Top