2002 x-20 wont rev over 3700ish

[dorsey.sean]

Ok first I'll admit I'm not the most knowledgeable on 2 stroke engines. I have the M2 engine. I have read about misfiring causing a revving issue. Compression is 125-130 on all cylinders. I put new plugs in and then removed them after the last trip (approx 1 hour on plugs). Looking at the plugs I'm leaning towards a misfire on 1&4 unfortunately I didn't have my inline tester with me when I took it out. I bought the boat last year and didn't have a chance to take it out until April. I purchased it from my neighbor and he told me it didn't have any issues before it sat (1 year in his driveway and 1 year in mine).

plugs are in order
12
34
56

 

[dorsey.sean]

guardian has been removed

 

[Tim75]

The M2 is the drive system. What engine do you have? What year?

Looks like #4 injector is dead. #3 is similar, but not quite as bad. The injector harness is 4 wires. One is common. Each of the other wires fires 2 injectors. Be careful of running any more because if a spark plug is dry, you are not getting any gas or OIL into that cylinder.

 

[dorsey.sean]

is there a resistance test for the injectors or am I looking for a wire problem? I do have an electronic service manual I bought online. I also fixed some corroded wires on the black box on top of the engine. The boat is a 2002

 

[Tim75]

Sat in somebody's driveway about 15 years..........

Engine is a Gen 1.

There is a resistance test that can be done. But by the time you are ready to do it, they are almost in your hand. These are Keihein (sp?) Japanese injectors that seldom completely fail. An injector shop can take them apart if required.

Harness- round, 4 wires, down low, starboard side. Pulls straight apart. Check for clean connections. Main harness- from ECM- round connector, many wires, in a bracket, starboard side. Has a retainer nut that holds harness together. Open carefully and check for clean connctions. No green connctions allowed. Check all the ground connections on the engine. There are at least 3. On the ECM, on the coil plate, big black one at or near the starter.

 

[dorsey.sean]

hahaha sounds like I should be boat shopping instead, I will check out the wiring and report back. Thanks for the help Tim

 

[dorsey.sean]

Grounds are not a clean as I would like, I am going to get a wire wheel and correct them. If I found the injector plug in pics 1&2 they seem ok, maybe a little contact cleaner would help. Picture 3 is a random brown wire I see hanging in the bottom and picture 4 maybe a pin pushed out?

 

[Tim75]

Grounds are not a clean as I would like, I am going to get a wire wheel and correct them. If I found the injector plug in pics 1&2 they seem ok, maybe a little contact cleaner would help. Picture 3 is a random brown wire I see hanging in the bottom and picture 4 maybe a pin pushed out?

Be careful that you don't remove too much material when cleaning connectors.
I remember there is at least one orphan wire on my engine. Zip tie it to a safe place. Pic 4- looks like the pins are installed from the face you are looking at. Not sure how they could "push Out". How do the pins look on the other half (pic 4)?


View attachment 48577View attachment 48578View attachment 48579View attachment 48580

 

[dorsey.sean]

Not sure how they could "push Out". How do the pins look on the other half (pic 4)?

Sorry I work on cars and we see where the pin gets loose in the connector not allowing the male side to go into the female side. The male pins are clean but Im not sure they will reach that one pin on the bottom. I looked on my wiring diagram and that is pin 14 (it goes to the head temp sensor and tps) not sure if that will cause my issue.

After I clean my grounds and spray contact cleaner into the connectors how can I test the injector? Take the plug out and see if fuel gets sprayed out of the cylinder?

 

[Tim75]

If there is a wire at those questionable holes can you push the wire back in? Of coarse, you will have to hold those wires in place as you reassemble the connector,

There is mention in the book about looking for injector spray. You will need to kill the ignition (all six) because you will have to crank with the throttle at half or more. You don't want the engine to actually start at that point. I hope you are very acrobatic or have a very good camera.

Any wire to/from the tps is an issue. The ecm defaults to full rich when the tps fails (or is disconnected).

 

[dorsey.sean]

Sorry @Tim75, I had surgery and my wife wouldn't let me mess with the boat. I did some of the troubleshooting tests from the service manual (plenty to time to read) and my #1 trigger has 26k ohms while the other 2 are testing in the 1100-1400 range. These are also the same wires I found corroded earlier. I can't find part numbers in my manual though. Where can I find the part numbers for the control module and trigger assy? Should I replace the stator while i'm in there?

 

[Tim75]

There are no part numbers in the service book.
Most Merc dealers that sell online have part number breakdowns. Crowley and BAM Marine are 2 that I know.

If you are checking the trigger wire pairs, (3 pair), it seems you have found the problem.
You can find the p/n and order from ebay. CDI brand seems OK, so far.

If your battery is getting charged, your stator is OK.

Use the proper flywheel puller, or you can crack the flywheel.

 

[dorsey.sean]

@Tim75
I replaced the trigger and it fired right up, revved it up a couple times then as I got it back to idle it stalled and won’t restart. Is there something I could have done wrong? I did go with the CGI trigger

 

[dorsey.sean]

Seems to have good spark, tested 2 and 4