First start up of 2 year rebuild. Back fires from intake manifold !!!

[spybot]

Johnson 140hp 1980 Crossflow
Total rebuild/refresh 2 years ago
New pistons rings ect ect all balanced and lightend ect CCM Sport reeds new carb kits.
The motor has not been started in 2 years since the build.
Got i running today but was misfiring and back firing from intake manifold.
1 I know i will have to take the manifold of and reseal but is there something i am missing ???
What may cause her to back fire out the side of the motor ????

 

[daselbee]

First thing I look at when an engine is backfiring is ignition wiring problems. Orange primary wires crossed, secondary plug wires crosed...something like that.
If you are getting intake backfires, you can pretty well kiss those CCMS reeds goodbye. I installed a set, first backfire set them on fire, and I replaced them with the original steel reeds.

 

[spybot]

OK will check the wires. I was certain i had them Blue/Orange on top but will double check them. Hopefully the reeds are 100% I had to order them in from the US (I stay in Scotland) Not sure if they still offer a guarantee after 2 years

 

[spybot]

Need to edit the first post.
The back fire came from the side of the intake !!! Guess i hadnt sealed it properly

 

[daselbee]

Still...think about it....the crankcase experienced a mini explosion in it. Not the cylinder and head area...the crankcase. So, the spark occurred when the piston was at the bottom of the stroke, where the fire could run down past the intake port and ignite fuel that is in the crankcase cavity. Spark plugs/coils are wired wrong....my opinion.

 

[oldboat1]

Do some preliminary forum searches here. (e.g., https://forums.iboats.com/forum/eng...nrude-outboards/586532-1980-johnson-140-hp-v4 ).

 

[spybot]

Still...think about it....the crankcase experienced a mini explosion in it. Not the cylinder and head area...the crankcase. So, the spark occurred when the piston was at the bottom of the stroke, where the fire could run down past the intake port and ignite fuel that is in the crankcase cavity. Spark plugs/coils are wired wrong....my opinion.

Got Daselbe 100% The coil primaries MUST BE WRONG. Going to get the intake off today and check the reeds. Chris Carson has told me "If the reeds are shot he will send me out another set" That is true customer service.

 

[havoc_squad]

I might suggest to ground the spark plug wires and mark flywheel every 90 degrees from Top Dead Center, then check with timing light each spark plug wire.

I will probably do that when I have to put my v4 90 degree crossflow motor back together.

It will help me make sure I have spark and at the right time.

 

[daselbee]

I might suggest to ground the spark plug wires and mark flywheel every 90 degrees from Top Dead Center, then check with timing light each spark plug wire.

I will probably do that when I have to put my v4 90 degree crossflow motor back together.

It will help me make sure I have spark and at the right time.

Very good suggestionby havoc to index the flywheel. Very good.

 

[Faztbullet]

Is this the one you played with porting?

 

[spybot]

OK will index flywheel. You are correct Faztbullet this has the porting done.
i Thinnk i have found the reason for the sdie blow out. I had added the stuffer blocks to the intake. When i took of the intake they were sitting proud of each cage. So i took out the dremmel and cut the recess that each screws sits in a little deeper. This will let the intake make better contact with the block. I think this is the only way the side blow out could have happend.
I have still to find the casue of the miss fire but im sure the side blowout was caused by ill fitting reed stuffers.
I have bent one of the CCM reeds with the back fire. I had lapped the cadges for a perfect fit. Now one the leafs is not closed completely.
Chris from CCM had messaged on S&F if they were toast he would sort out another set from me.
Just a case of waiting for them to arrive.

 

[spybot]

Is this the one you played with porting?

I really only cleaned the flow up from intake and got rid of casting marks. Never touched the ports. Only chambered them slightly after the block was honed.

 

[Faztbullet]

Richen up the idle jets

 

[spybot]

Richen up the idle jets

I have gone one size up from standard already
What size should i go for ?

 

[Faztbullet]

1-5/16 carbs ???

 

[spybot]

Yeah 1 5/16th Carbs The following has been done to the intake side of the motor.
I have only put in the explanations of what each part of the work does for the readers who are not familiar with engines.No dis-respect to you opr others.
I polished the the barrels after the butterfly (Made sure the Idle circuit was ultra clean.) Matched the carb flow to the intake manifold.
The manifold has had all the casting marks removed and roughend up the walls on the way to the reeds (helps atomize the fuel)
Then i removed the rough edges on the reed cage then lapped the surfaces for 100% contact.
So hopefully it will be back and running asap.

 

[spybot]

edit

 

[RaisedByWolves]

I read somewhere that lapping the reed mating surface was not good.

Something about the possibility of this making them stick in place and or flutter.

 

[oldboat1]

flutter, maybe, unless the lapping is dead on perfect, along with the reeds -- otherwise issues like poorly adjusted or warped secondary air doors in an old quadrajet.

 

[racerone]

This ' rebuild " will be discussed for days.----Perhaps go to 50 posts or more.