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Need lot of help motor surges

G

George#1

New member
:confused: Ok, here we go, I will try to make a long story short. I'm retired so I'm on a fixed income and don't have the extra money to to take it to a pro. I have a Johnson 150hp j150plees . In late may early June it began to act like it was running out of gas, the gauge showed I had close to 1/4 of a tank of gas but the gauge maybe off. So I added 10 gal. NO FIX. I checked the primer bulb and it was soft, I replaced it with a new one, NO FIX. Replaced the gas line from the tank to the bulb and the line from the bulb to the motor, NO FIX. I replace the spark plugs & wires with new ones and did increase my speed but still surge when trying to go wot. Now I turn to the vro2 pump and put a kit in the fuel side of the pump, NO FIX. Primer bulb still soft but when I pumped it I did have a leak at the vapor bowl, new kit, NO FIX. Now I turn to the carbs, put in new kits, took off the throttle bodies and cleaned them really good , I believe. NO FIX. Also replace all or most of the spring clamps with new clamps just in case I had a leak around the fittings. I'm really running out of ideas, need some good advice. PLEASE! Could it be something electrical
 
Use a timing light as a " poor man's scope " hook it up to one cylinder at a time out on the water.---Observe the flash of the light when motor falters.
 
Have you squeezed the primer bulb when the engine starts to surge? If that stops the surge you still have a leak of some kind in the fuel supply plumbing! Also make sure the fuel tank vent is not plugged up, that will starve the motor of fuel!
 
Yes, I had my cousin pump the primer while running. Didn't help. As for the vent I have removed the gas cap and tried running still no better.
 
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So you think it might be the spark? Earlier this year I had problems with no spark, replace the power pack with a new one, the rectifier with a new one, and the strator with a (good)? Used one . Maybe bad coil?
 
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George, I am not a pro marine mechanic like racerone, but he is probably steering you down the right path. Your ignition system could be loading up for some reason, or you could be intermittantly dropping a cylinder on and off which would produce a surging effect.
Do you have a maintenance manual? That will give you all of the troubleshooting procedures for the ignition and save you money in the long run by not buying parts that you don't need. If you don't have one you need to get one as soon as possible! The timing light will show you which cylinder is trying to drop out or if it is going thorough a significant timing change if you take recerone's advice

Keep us posted!.
 
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