Evinrude 140-HP Misfire

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
Don SSDD
Posts: 313
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Location: Nova Scotia

Evinrude 140-HP Misfire

Postby Don SSDD » Thu Sep 01, 2016 7:16 am

My 1994 [Evinrude 140-HP outboard engine that employs] loop-charging has a misfire. [The Evinrude 140-HP engine] would normally [accelerate to] 5,500-PRM, but now only [accelerates to] 4,000-RPM. It sounds like it has one cylinder not firing, and one spark plug is very black.

The spark plugs are new in the spring [of 2016], and the boat ran fine until this happened. After the misfire started, I noted the [1994 Evinrude 140-HP engine's] spark plug wire [integrity] was questionable. I installed new spark plug wires.

I have read that a lean condition could [cause a cylinder to] overheat and ruin a cylinder.

Should a compression test show low compression on a bad cylinder?

Is there anything electrical that would cause one cylinder not to fire?

I am mechanical on old cars, but lack real experience on old outboards or on two-stroke-power-cycle engines. Any suggestions or help would be appreciated.

Thanks,
Don
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Robertl211
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Joined: Mon Aug 22, 2016 8:28 pm

Re: Evinrude 140-HP Misfire

Postby Robertl211 » Thu Sep 01, 2016 8:00 pm

A compression check can definitely tell you if there is a problem with a cylinder.

Depending on the outboard, 2- or 4-stroke, how hard it was run, year it was built, condition of bearings, hours, etc., the compression will be varied. A good-running two-stroke looper should be around 100 to 130-PSI--big range I know--but the most important thing is to make sure they are all within 10-15% of each other. If you have a bad cylinder, which I suspect you do, it will be painfully obvious with the compression reading. It will read 100, 105, 103, 65 across the 4 cylinders. If you have good compression across the board then it is time for a spark check, carb cleaning, and possibly fuel pump.

To test compression:

go to advance auto and buy a compression tester with the gauge, hose, and multiple attachments. The OMC looper will be a common size
Pull all 4 plugs and move the plug wires away from any ground
Install your compression test gauge in one cylinder and with the engine in WIDE OPEN THROTTLE POSITION crank until the gauge stops increasing.
Continue this process for the rest of the cylinders. Don't start with the bad cylinder, do it after you have a couple good readings for comparison.

If you find low compression in that one cylinder, you need to weigh your options. A used 140 OMC looper can be found for around [$1,500] tops. OR you can find a used power-head. That is if yours has been maintained, and isn't corroded and will come apart. Old engines in saltwater usually are difficult. It would cost about [$2,500] for a marina to rebuild yours so that is probably out of the question. Might be time to upgrade to a 4 stroke!

Hope this helps!
1999 Regulator 26FS twin 250 ox66
1972 Whaler 13' Mini-project
1983 Seaway 19' - 75 OMC - Restoration in progress
http://www.thehulltruth.com/boating-...ld-thread.html

Don SSDD
Posts: 313
Joined: Fri Oct 23, 2015 6:58 am
Location: Nova Scotia

Re: Evinrude 140-HP Misfire

Postby Don SSDD » Thu Sep 01, 2016 8:39 pm

That is very helpful Robert.

The engine has likely seen hard use in saltwater. I bought it with the Guardian two years ago.

Don
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Robertl211
Posts: 12
Joined: Mon Aug 22, 2016 8:28 pm

Re: Evinrude 140HP 1994 Miss

Postby Robertl211 » Fri Sep 02, 2016 2:53 am

In that case you'll probably be looking at a bad cylinder. If the compression test comes back good then it most likely is an easy fix. However, the discolored spark plug and sudden loss of performance is usually an indication of a bad cylinder. This is a common failure with V4 and V6 two-stroke-power-cycle engines.

Good luck. Let us know what you find.
1999 Regulator 26FS twin 250 ox66
1972 Whaler 13' Mini-project
1983 Seaway 19' - 75 OMC - Restoration in progress
http://www.thehulltruth.com/boating-...ld-thread.html

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Fri Sep 02, 2016 6:42 pm

Is there anything electrical that would cause one cylinder not to fire?


The electrical problems that prevent spark plug firing on a two-stroke-power-cycle loop-charged 1994 Evinrude 140-HP outboard engine are the same as on any spark-ignition engine: lack of proper voltage at the spark plug. Since you are familiar with other engines you should be familiar with those items that can cause low voltage at the spark plug.

Most likely your 1994 Evinrude outboard engine uses an unrepairable assembly called the Power Pack to generate the primary spark coil voltage for the spark ignition coils. It is not unusual for one cylinder's circuit in the Power Pack to fail or at least to fail on an intermittent basis.

Most likely your 1994 Evinrude outboard engine uses an individual spark coil for each cylinder. These coils can go bad, have bad connections to ground, or leak their secondary voltage to ground. Observe the coils in a very dark environment to visually detect loss of spark to ground.

Most likely your 1994 Evinrude outboard engine uses an individual spark wire for each cylinder. These wires can go bad, have bad connections to either the coil or the plug, or leak their voltage to ground. Observe the wires in a very dark environment to visually detect loss of spark to ground.

In order to assess if the cause of the misfire is related to lack of spark, you should perform a spark test.

Do you have the factory service manual for this engine?

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Fri Sep 02, 2016 6:54 pm

...a bad cylinder...is a common failure with V4 and V6 two-stroke-power-cycle engines.


Loss of a cylinder due to bad compression is not really common in two-stroke-power-cycle outboard engines. The vast majority of them never have this problem.

Before agonizing needlessly about the loss of compression, perform a compression test. The procedure is given in an article at

Assessing Used Outboard Engines
http://continuouswave.com/whaler/refere ... Check.html

Follow the advice given in the above article to assess your used outboard engine.

Robertl211
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Joined: Mon Aug 22, 2016 8:28 pm

Re: Evinrude 140-HP Misfire

Postby Robertl211 » Fri Sep 02, 2016 8:19 pm

jimh wrote:
...a bad cylinder...is a common failure with V4 and V6 two-stroke-power-cycle engines.


Loss of a cylinder due to bad compression is not really common in two-stroke-power-cycle outboard engines. The vast majority of them never have this problem.

Before agonizing needlessly about the loss of compression, perform a compression test. The procedure is given in an article at


Loss of a cylinder due to bad compression is incredibly common, I went to school for this, and worked in the industry. Especially on V4 and V6 2 stroke outboards, where the design of some of these cooling water passages leave certain cylinders on some models susceptible to overheating. I have personally found many of these engines with bad cylinders, and have rebuilt numerous V4 and V6 OMC outboards due to this problem.

Spark test is the first thing you should check, followed by a compression test. These are both easy and shouldn't take more than 10 minutes to accomplish both. Unless you want to be frustrated over electrical problems that may or may not be present.

These engines are known for electrical problems in the charging circuit within the ignition system. That being said, a spark test will tell you if that is a problem, and compression test will tell you if a mechanical problem.
1999 Regulator 26FS twin 250 ox66
1972 Whaler 13' Mini-project
1983 Seaway 19' - 75 OMC - Restoration in progress
http://www.thehulltruth.com/boating-...ld-thread.html

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Fri Sep 02, 2016 8:46 pm

What is "common"? More than half of all engines?

It is common for 22 year old engines to need service. Are you trying to say the all or the majority have lost compression?

Robertl211
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Joined: Mon Aug 22, 2016 8:28 pm

Re: Evinrude 140-HP Misfire

Postby Robertl211 » Fri Sep 02, 2016 8:59 pm

jimh wrote:What is "common"? More than half of all engines?

It is common for 22 year old engines to need service. Are you trying to say the all or the majority have lost compression?



No. Common would be a problem that is not unheard of, or not UNCOMMON. I'm not sure why you think that means half of all engines, but quite a few engines have this problem. With his symptoms the first test I would do is a compression test. Yes a 22 year old engine will need to be service, and no, most likely it will not have a bad cylinder. But again, with regard to his symptoms, it would be the first thing I would check, followed by a spark test. Because in the event both of those come back good, he has wasted only about 10 minutes, [$30](high estimate) on two tools that everyone with a gasoline engine should have in their shop anyway, and have established a solid baseline to start further troubleshooting.

I'm not quite sure why you feel you need to fight me on every post, especially when I'm trying to give some solid advice to someone who asked for help.

Thanks.
1999 Regulator 26FS twin 250 ox66
1972 Whaler 13' Mini-project
1983 Seaway 19' - 75 OMC - Restoration in progress
http://www.thehulltruth.com/boating-...ld-thread.html

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Sat Sep 03, 2016 8:23 am

I am not attempting to "fight" you. You should not expect that your comments posted here will be immune to further comments about them. The forum tries to collect useful information. To seek clarification and elaboration on advice given should not be consider as a confrontation or fist-fight.

I am attempting to dispel the notion you introduced that loss of compression is common in two-stroke-power-cycle engines. I doubt that either of us has any actual statistical data on the frequency for two-stroke-power-cycle engines to lose compression in a cylinder.

The problem with assessing this from the perspective of being a repair mechanic for two-stroke-power-cycle engines is that ALL the engines you see are engines that need repair. Thus it is not surprising for a repair mechanic to see engines that need repair that have problems in cylinder compression. But this is not really indicative that all two-stroke-power-cycle engines will be likely to to have this problem.

Common means occurring or appearing frequently. I agree, for engines that exhibit loss of combustion on one cylinder, a frequently seen cause is loss of compression. Another common cause for loss of combustion in one cylinder is loss of spark. Or loss of fuel. Or improper fuel-air mixture ratio. But I disagree that it is common for all two-stroke-power-cycle engine to have failure of combustion on one cylinder due to low compression.

I have no argument with the recommendation to perform a compression check; indeed, I suggest that same action in my own reply.

Until we have the results of a compression check, it seems premature to begin to project what sort of repair costs might be needed and what sort of future engine purchases will be necessary.

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Sat Sep 03, 2016 8:43 am

DON--if you want to perform your own diagnosis and repair of running problems with your 1994 Evinrude 140-HP loop-charged outboard engine, I recommend you purchase the factory service manual for that engine. The OMC factory service manuals from that period are extremely well written, are profusely illustrated, and give very detailed, step-by-step procedures for making a diagnosis and repair of the engine. The cost of the manual will typically be less than one hour of labor from a qualified technician. With the manual available to you, you will become a much more effective repairman for your own engine.

Although your 1994 engine is 22-years-old, you may be able to find a dusty copy of the factory service manual on the shelf of a dealer. Buy it.

Don SSDD
Posts: 313
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Location: Nova Scotia

Re: Evinrude 140-HP Misfire

Postby Don SSDD » Sat Sep 03, 2016 12:22 pm

I do have the Clymer B733 EJ 91-94 Manual. I think I looked for the shop manual at the time and then bought this when I couldn't find one.

My concern with working on a 2 stroke outboard is a lack of familiarity with the whole setup. Multi carbs, a charge coil, power coil, 8 sensor coils, power pack, 4 ignition coils. Lots of coils?

On my old GM Chevies, you have 1 coil, usually 1 carb, 1 set of plug wires, points (or I use Pertronics), the list is short of things to check, unlike this outboard, and I have a good idea where to start. I've worked on 283, 327, and 409, they all work the same.

The first thing I did was a compression check, I had the tool for that. To my relief, all 4 cylinders were in the same range, 130-135 lbs. The next thing I did was change the spark plugs, even though the old ones were almost new, maybe 10-20 hours on them. It started and ran very good, I let it warm up a bit at slow RPM, it ran fine and then back up to 5500 with no problems. Seems to be working OK so I'll get some water time and hope all is OK.

Thanks very much for the advice.

Don
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Don SSDD
Posts: 313
Joined: Fri Oct 23, 2015 6:58 am
Location: Nova Scotia

Re: Evinrude 140-HP Misfire

Postby Don SSDD » Sat Sep 03, 2016 12:24 pm

I should add, I only started wrenching on anything about 13 years ago, I work in an office and never get my hands dirty. But I enjoy figuring out mechanical things.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

jimh
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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
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Re: Evinrude 140-HP Misfire

Postby jimh » Sat Sep 03, 2016 3:45 pm

Two-cycle outboard engines have been ahead of automotive engines in their ignition system for some time. Cars now use individual coils for each cylinder; outboard engines have been using that approach for some time. Outboard engines do not have distributors.

The common electrical component in outboard engines is the stator winding that generates the electrical power for spark ignition. This electrical power is controlled by the PowerPack. The PowerPack switches the electrical power from the stator winding to the primary spark coil winding for each cylinder in the proper sequence. The PowerPack is controlled by a signal from the timer base.

Spark ignition timing is controlled by a dedicated sensor coil that is positioned in a unique location; this coil is excited by the flywheel magnets. Timing is adjusted by physical rotation of the entire coil base assembly around the crankshaft. Spark advance can be created electronically or by actual movement of the timer base plate or by a combination of the two.

Perform a spark test to determine if there is a loss of spark in the affected cylinder. A useful tool for performing a spark test is an in-line spark tester. I have used an in-line spark tester made by Lisle with good results.

GENERAL ARRANGEMENT OF SPARK IGNITION COMPONENTS ON OLDER OUTBOARD ENGINES

In a spark ignition circuit you generally find the following components:
--plug
--high-tension wire
--coil, high voltage or secondary winding
--coil, low-voltage or primary winding
--low-voltage wire
--coil driver circuit
--driver circuit timing source
--driver circuit voltage source

The driver circuit timing source is usually a pick-up coil under the flywheel which is excited by magnets. These coils are sometimes called the "timer base." The driver circuit voltage source is usually one or more coils under the flywheel which are excited by magnets.

All these coils are sometimes integral with other coils and are called "the stator." On some engines there may be dual coils for generating the driver circuit voltage, each optimized for a certain engine rotation speed range, and these are sometimes called "the low speed stator" and "the high speed stator."

If you are not getting spark, begin at the spark plug and work backwards toward the stator. If you have an engine with multiple cylinders you have a source of alternative parts to swap into the circuit for testing for many of the elements.

An in-line spark tester is a good way to determine if your cylinder is getting spark while the engine is running and the spark plug is in place. An in-line spark tester is a test device which can be inserted in the high-voltage spark wire. They typically have one connector which mimics a spark plug electrode and another which is a spark plug boot connector. You can remove a spark plug wire from the spark plug and insert the in-line spark tester on that cylinder. The tester has a small spark gap contained inside a transparent glass cylinder. This allows you to visually observe the spark. You can typically find these at stores that sell automotive supplies. I got mine from master mechanic David Zammitt at Lockeman's Boat and Hardware.

20610 LISLE In-line Ignition Spark Tester
Image

jimh
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Re: Evinrude 140-HP Misfire

Postby jimh » Sat Sep 03, 2016 3:53 pm

Some insight into electrical components can be made by resistance checks. A good service manual will give you advice on how to perform resistance checks and what the anticipated resistance values ought to be. I don't have any data for your particular engine to pass along. Perhaps some other participants in the thread may have access to that data and can share it with you.

Don SSDD
Posts: 313
Joined: Fri Oct 23, 2015 6:58 am
Location: Nova Scotia

Re: Evinrude 140-HP Misfire

Postby Don SSDD » Sat Sep 03, 2016 6:12 pm

I like that tester Jim, great tool and not expensive.

Don
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia

Robertl211
Posts: 12
Joined: Mon Aug 22, 2016 8:28 pm

Re: Evinrude 140-HP Misfire

Postby Robertl211 » Sun Sep 04, 2016 8:42 pm

Glad to hear it was only a spark plug. Cheap fix. Make sure all of your plugs are gaped correctly.

You might consider adding some fuel system cleaner when you fill the tank, or having the carbs cleaned. Might help in the future to avoid fouling plugs. When I run my 2 strokes just before I get back to the harbor I will open them wide to burn off some carbon in the cylinders, exhaust etc. I also run a fuel system cleaning additive such a seafoam or yamaha ringfree which helps immensely with not fouling plugs.

Hopefully the plug fixes the concern permanently but if only that one keeps getting fouled than you'll have to look deeper into the engine for problems, and I would start at the carbs.
1999 Regulator 26FS twin 250 ox66
1972 Whaler 13' Mini-project
1983 Seaway 19' - 75 OMC - Restoration in progress
http://www.thehulltruth.com/boating-...ld-thread.html

Don SSDD
Posts: 313
Joined: Fri Oct 23, 2015 6:58 am
Location: Nova Scotia

Re: Evinrude 140-HP Misfire

Postby Don SSDD » Mon Sep 05, 2016 6:45 am

Thanks Robert, I do run Seafoam a couple of times a year in everything I own with a carb.

Don
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
Nova Scotia