Need engine help and advise

S

smkinnan

Member
Guys (and gals), I am in serious need of some help here. I bought a 77 V20 center console late last year and started saving to get the motor repaired (carbs rebuilt, water pump, etc...) and to re-do the transom (with arjay per the suggestions on this site).

Well, last night I did a compression test on the motor (a 1991 200 Evinrude) and found out that the #1 cylinder has little or no compression and that the remaining cylinders have approximately 75 psi each. Since I haven't been able to start the motor I did the test with the engine cold. I have been told that I should do the test when the engine is warm but I obviously can't at this time :( It also appears that I'm not getting any spark.

Anyways, does anyone have an idea what I should do at this point? Is the motor most likely trash or can it be rebuilt fairly inexpensively? I realize I haven't given much information here but I don't know what to do next.

If I decide to change the motor, what are my best options? I don't have a ton of money and can't finance one of those new 4 stroke Yamahas (although I would love to). I see lots of motors for around $2k to $4k on eBay and on Craigslist but can't make heads and tails about whats good and bad. I feel like I've already made a big mistake but I love the boat and want to keep it, and really just want to take my son fishing. Any help is appreciated. Thanks for your time....
 
I'll let the guys that actually know what they are talking about give you a proper diagnosis but I'd sit down while reading because I dont think its going to be good.

Doing the test while warm isnt going to make up that kind of difference you definitely got something major (major to me anyway because I dont know how to tear down a motor) going on.

Sorry to hear of your troubles....biggest fear most everyone has when buying a used boat....hopefully you'll get out this jam with a dollar figure you can live with and start fishing!
 
I would pull the heads and have a look inside, mid 80's omc and upwards motors didn't have a lot of compression to begine with. Main concern is what is causing the 0- low compression, could be something as simple as a head gasket. I would worry about the low compression right now before getting to the spark. Compression test should be done without spark anyway.

If you pull the heads and see scoring on the cylinder walls and/or pocketing on the head(s) a rebuild is in order. Some at this point would trash the motor depends on your mechanical capability a rering and hone isn't beyond most backyard mechanics.

Brian
 
I pulled the head on the side where the cylinder had little compression. I DID in fact have a bad head gasket, plain as day. :sun:The thermostat also looks like it is well beyond its normal life. I will replace both sides. The cylinders on that side look absolutely beautiful. I am completely amazed. Thanks for the suggestions guys. I will update shortly. :beer:

any suggestions on where would be the best place to get parts for these things? Internet? Local guy? I live in the Orlando area and I've noticed lots of you guys that are in this area.

by the way, any ideas what might be the cause of the lack of spark? :head:
 
spareparts said:
was it no spark at all, or just on one or more cylinders?
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Thats a great question and I think I know where you are going with it. I noticed the individual coils last night when I pulled the head off of it. I guess if there is no spark in 1 cylinder, one of those coils could be the culprit!?! Alternatively, if there is no spark at all there may be another componant that is bad. I guess I assumed that there was no spark since it didn't act like it wanted to fire at all. I only tested one cylinder for spark though. I guess I need to dive into that a little further. Thanks so much for the reply....

Do you guys have a favorite place to buy parts for these things???
 
if its only one cyinder with no spark, pull the coil an clean the graound strap on the coil(better do it with all of them), if it has no spark, disconect the main engine wire harness, tehm jump the starter selenoid(red to yellow/red) adn see if it sparks, if it does then, you have a harnes or key switch issue
 
spareparts said:
if its only one cyinder with no spark, pull the coil an clean the graound strap on the coil(better do it with all of them), if it has no spark, disconect the main engine wire harness, tehm jump the starter selenoid(red to yellow/red) adn see if it sparks, if it does then, you have a harnes or key switch issue
Click to expand...

Thank you so much....I will check this stuff out and report back ;) :hi:
 
I know how you guys like photos so I thought I post a couple on this issue....
 

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I was going to suggest you decarb the head and cylinder tops while you have it apart but that looks clean enough to leave alone. You could now spray some PB blaster directly on the rings though just to loosen them up. I would get the headgaskets and button her back up and recheck compression. I bet you are going to be pleasantly surprised. Get her healthy on all six and I can find your lost spark.

Brian
 
brisboats said:
I was going to suggest you decarb the head and cylinder tops while you have it apart but that looks clean enough to leave alone. You could now spray some PB blaster directly on the rings though just to loosen them up. I would get the headgaskets and button her back up and recheck compression. I bet you are going to be pleasantly surprised. Get her healthy on all six and I can find your lost spark.

Brian
Click to expand...


Thanks so much, I really appreciate your help. I'll exactly what you are talking about.
 
brisboats said:
I was going to suggest you decarb the head and cylinder tops while you have it apart but that looks clean enough to leave alone. You could now spray some PB blaster directly on the rings though just to loosen them up. I would get the headgaskets and button her back up and recheck compression. I bet you are going to be pleasantly surprised. Get her healthy on all six and I can find your lost spark.

Brian
Click to expand...

ok, got the compression problem fixed with a new set of head gaskets. I installed new thermostats and spark plugs as well. I went ahead and pulled each one of the coils loose and cleaned the contacts on them. Alas, it appears as though I STILL have no spark at all. :head: Starter cranks like crazy and the TNT works well but no spark. What can I look for to find a way to fix the spark issue?
 
Did you disconnect the red plug and jump it per Spare? See #2
OMC Six Cylinder Engines
No fire at all:

1. Note: If the engine fires with the spark plugs out but not with them installed, the timer base is likely weak or the engine is not spinning fast enough. See # 6 and #8.
2. Disconnect the black yellow kill wire and retest. If the engines now has fire, the kill circuit has a fault-possibly the keyswitch, harness or shift switch.
3. Disconnect the yellow wires from the stator to the rectifier and retest. If the engine fires, replace the rectifier.
4. Check the stator resistance. You should read approximately 500 ohms from the brown wire to the brown/yellow wire.
5. Check the DVA output from the stator. You should have a reading of at least 150V or more from the brown wire to the brown/yellow wire (while connected to the pack) on each bank.
6. Check the timer bases resistance from the white wire to the blue, green and purple wires. Reading should be 10-20 ohms.
7. Check the DVA output from the timer base. A reading of at least 0.5V or more from the white wire to the blue, green and purple wires (while connected to the pack) is needed to fire the pack.
8. Check the DVA voltage on the white wire to engine ground. You should have a reading of at least 150V or more (while connected to the pack). If the reading is low, disconnect the trigger wires from the pack and recheck the white terminal on the pack. If the voltage jumps up to an acceptable reading, the timer base may have a problem in the internal wiring (A thin spot in the insulation on one wire).
9. Check the cranking RPM. A cranking speed less than 250-RPM will not allow the system to fire properly.

No fire or Intermittent on One Cylinder:

1. Check the timer bases resistance from the white wire to the blue, green and purple wires. Reading should be 10-20 ohms.
2. Check the DVA output from the timer base. A reading of at least 0.5V or more from the white wire to the blue, green and purple wires (while connected to the pack) is needed to fire the pack.
3. Check the DVA output on the orange wires from the power pack while connected to the ignition coils. You should have a reading of at least 150V or more. If the reading is low on one cylinder, disconnect the orange wire from the ignition coil for that cylinder and reconnect it to a load resistor. Retest. If the reading is now good, the ignition coil is likely bad. A continued low reading indicates a bad power pack.
 
Direct Voltage Adapter - Fluke and many multimeter have it, or can get a adapter...Start with the basics first leave the advance analyses for later you may find the the issue to be simple ...
 
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