rough running v4 90hp

[nightflight]

I have the same old project from april. 90 hp 93 model v4 that ran away on fire up. bad carbs was the . It dropped to 2 cylinders on one side. I faught it for a few days and quit, got a different power pack and tried again. It back fired and then when I cranked the fly wheel spun loose. I guess the bad running was a slipped flywheel.
$3 key way,, lapped the shaft and wheel.Torqued to around 105.
Now it's running again but one side seems to not be firing well. the two cylinders starboard side,,feel cool but the spark is enough to give you a jolt through insulated pliers.
Compression was 120's on three and one at about 105. Can't remember which was which ,,but think the cool cylinder may have been the low one.
Carbs were recent rebuild's off my old motor.They are good..

What do you recommend next? other than the "Italian tune up" ( running the heck out of it to see if it'll clear out.

 

[coolguy147]

Re: rough running v4 90hp

never heard of italian tune up lol


do a decarb someone should come by with the instructions

 

[tashasdaddy]

Re: rough running v4 90hp

besure you are getting fuel to that cylinder, you have 2 2 barrel carbs. each barrel is for a cylinder. if you motor has the schrader valve on the primer solenoid, get a can of BRP Engine Tune, with the hose to connect to the schrader valve, follow directions. if you do not have the schrader valve, do it this way.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

afterwards compression.recheck

 

[nightflight]

Re: rough running v4 90hp

Run tested the engine, under load it starts to choke down, with the primer key down and 3/4 throttle it runs with power and real smooth. I've been here before and its high speed jets. Right??
Is there a good place with pictures on the v4 carb rebuild?
Local backyard guys want $80 per hour for 1 1/2 hours,,, if I take the things off and put them on.
Should I do the bad one or both?
they were both done about 25hrs back.
I have the old plastic carbs on a spare engine are they worth touching?
Should I just clean out the clog or replace all the stuff?

Is there an easy way to clean high speed jets without taking the whole thing apart?
There must be some kind of trick?