Can the base of engine work? Two to bolts under engine are rusted and can

[achris]

I think that's only firing on 3 cylinders. Check you have spark on all spark plugs, check the spark plugs themselves, check the rotor, cap and all the leads.

I'd do a 'plug pull' test. With the engine running, using good insulated pliers, pull each spark plug lead off one at a time. When the engine doesn't change, that's the cylinder with the problem. You should hear the spark 'cracking' as you lift the lead. No (spark) cracking, lack of spark is the problem. You hear the cracking, but the engine speed doesn't drop, you have a bad plug, or a bad cylinder (head gasket, valves etc).

Chris......

 

[liusigou]

I think that's only firing on 3 cylinders. Check you have spark on all spark plugs, check the spark plugs themselves, check the rotor, cap and all the leads.

I'd do a 'plug pull' test. With the engine running, using good insulated pliers, pull each spark plug lead off one at a time. When the engine doesn't change, that's the cylinder with the problem. You should hear the spark 'cracking' as you lift the lead. No (spark) cracking, lack of spark is the problem. You hear the cracking, but the engine speed doesn't drop, you have a bad plug, or a bad cylinder (head gasket, valves etc).

Chris......

The pressures are 140,140, 125-130,140. Always I can hear explosion voice while trying starting engine. I can see the smoke at the top after the explosion voice

 

[achris]

'Explosion voice', what's that? Backfire, maybe?

If it's backfiring, then maybe you have a valve tightened down too far, or the carb is too lean.

Chris...

 

[liusigou]

'Explosion voice', what's that? Backfire, maybe?

If it's backfiring, then maybe you have a valve tightened down too far, or the carb is too lean.

Chris...

Hopefully I can explain it a little better, when I try to start the engine, the engine starts to spin like normal, but after some time maybe a few seconds, there is a popping noise, smoke comes out of the top of the engine, and the engine stops on its own.

 

[liusigou]

It runs better and less shaking after I tested the cylinder pressure while the testing pressure. But it seems engine run slower and slower and stop in the end after I put into netural shift. even it stops after put it into reverse shift. I only adjust the lower shift cable on the top of engine. Should I adjust the other two cables?

 

[achris]

That sounds like a backfire. Check the valves clearances and the ignition engine timing.

 

[Scott Danforth]

Do a leak down test on cyl 3

 

[liusigou]

That sounds like a backfire. Check the valves clearances and the ignition engine timing.

I do not know what backfire means. there is an special explosion sound and then I can see the black smoke on the top of engine.

 

[nola mike]

I do not know what backfire means. there is an special explosion sound and then I can see the black smoke on the top of engine.

That's a backfire.

 

[liusigou]

I cannot start engine after I mount the outdrive. Link is the viedo of trying to start the engine with backfire. What issue is it? I can start the engine if the outdrive is not mounted. Should I replace all the spark? I think the coil has some issue.

New video by nengqiang liu

photos.app.goo.gl

 

[Scott06]

I cannot start engine after I mount the outdrive. Link is the viedo of trying to start the engine with backfire. What issue is it? I can start the engine if the outdrive is not mounted. Should I replace all the spark? I think the coil has some issue.

New video by nengqiang liu

photos.app.goo.gl

That sounds more like a lean sneeze than a backfire. Are you sure its getting gas? check for gas and spark should fire? Also verify the shift interrupt switch is not active as that will ground the spark

 

[liusigou]

That sounds more like a lean sneeze than a backfire. Are you sure its getting gas? check for gas and spark should fire? Also verify the shift interrupt switch is not active as that will ground the spark

Today I went to marine supplier with my coil, he tested my coil and told my coil is good. I can add some gas and also replace the spark. But how can I verify the shift interrupt switch?

 

[Scott06]

Today I went to marine supplier with my coil, he tested my coil and told my coil is good. I can add some gas and also replace the spark. But how can I verify the shift interrupt switch?

I think you just disconnect the wires at the shift interrupt.

Since it worked then it didn't suddenly, do you have a kill switch at the helm that may be tripped- do you have 12v at positive terminal of coil when cranking

To rule out a back fire (when spark plug fires but intake valve is open) have you done a compression test to verify valves are seating and verified the ignition timing and firing order

 

[liusigou]

I have just done a test for starting engine after I added some gas. the explosion and noise and smoke are still there, but did not shake any more. But after I pull the handle to be neutral, the engine stop and I could not start the engine any more.

 

[achris]

If the drive is of the boat, check that the shift slide isn't getting hung up when you move the gear lever. If that's not the problem, then it sounds like there's problems with the shift plate, involving the interrupt switch. Learn how the shift system works and then start checking it out.

The continued backfire on starting could be over advanced timing.

Chris...

 

[liusigou]

If the drive is of the boat, check that the shift slide isn't getting hung up when you move the gear lever. If that's not the problem, then it sounds like there's problems with the shift plate, involving the interrupt switch. Learn how the shift system works and then start checking it out.

The continued backfire on starting could be over advanced timing.

Chris...

Manual#6?

 

[achris]

Manual#6?

HOW TO: How the Shift Interrupt system works

Usually in the spring and summer we get a lot of posts regarding the shift system for the MC-1 (falsely referred to as Pre-alpha drives) to the Alpha 1 drives. There are a lot of wrong ideas on how and why the system works and why it's there to begin with. Maybe this will help explain how it...

forums.iboats.com

 

[liusigou]

Can anybody confirm that the wirings are correct or not for the four cylinders?

 

[Blorton]

I just wanted to chime in and say I really admire those of you chipping in and helping the OP, despite the serious language barrier. I am in awe.

 

[liusigou]

Sorry. I'd like to upload a picture to confirm the cylinders connections to distributor are correct or not.