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1999 115 johnson fast strike outboard smokes at idle and first start up

M

Millie Grace

New member
am new to this forum so hopefully all you experts can give me some advise and or direction. have just got this 1999 boat in the fall of last year so this engine is new to me. did some maintenance over the winter compression all 120 125 across all 4 cylinders. had a fuel leak so replace the manual choke lever solenoid and operates as it should now. overhauled the vro with a kit off of amazon found a diaphram rubber cracked. fuel system all good holds no leaks ball pumps up and holds pressure. noticed alot of blueish smoke when running with muffs in driveway but up to cottage for the season. engine has lots of power idle was a little poor when first in water but improved possibly old gas in tank. possible causes carbs need to be looked at.?? sucking air on the fuel inlet hose somewhere?? one way check valve at suction line to block not sealing??? gasket issues???? not sure why it smokes at idle only when you take it off plane and idle eventually the blue smoke returns. have been monitoring the oil consumption and seems normal?? have not pulled plugs to inspect hate working on the water. any advise would be very appreciated thanks bob
 
You have a VRO or air leak. When you return to idle the mixture is at 50:1 in carb. After a few minutes smoke should reduce as the oil mix is leaned due to less VRO cycles
 
faztbullet said:
You have a VRO or air leak. When you return to idle the mixture is at 50:1 in carb. After a few minutes smoke should reduce as the oil mix is leaned due to less VRO cycles
Click to expand...
first thanks for the interest and the reply. oil monitoring sensor on top of vro is working properly. the air leak being in a fuel hose to the vro or a gasket issue past the carbs?? possibly could there be some air bleeds plugged on carbs to richen mixture only at idle?? your thoughts
 
faztbullet said:
You have a VRO or air leak. When you return to idle the mixture is at 50:1 in carb. After a few minutes smoke should reduce as the oil mix is leaned due to less VRO cycles
Click to expand...
with an air leak ie gasket issue would you not think that engine would be running leaner and it really has no way to richen the mixture? therefore less smoke? have you heard of the one way valve at pulse line not sealing off properly
 
What one way valve on the pulse line.----Are you referring to the pulse limiter ???----Well , that item is not a one way valve.
 
racerone said:
What one way valve on the pulse line.----Are you referring to the pulse limiter ???----Well , that item is not a one way valve.
Click to expand...
yes the valve ob the pulse line might be sticking or providing not a variable pulse ot vro. yet it runs good at higher speeds no smoking just at idle and abit worse at first start up. never thought of tipping motor up overnite and trying in the morning?
 
That is called the pulse limiter.----It is NOT a one-way check valve.----It is a flow fuse for the VRO to protect from over pressure.-----Normal for the motor to smoke more at start up.----Just another example of how oil / lubrication of 2 strokes is mis-understood.
 
with an air leak ie gasket issue would you not think that engine would be running leaner and it really has no way to richen the mixture? therefore less smoke?
Click to expand...



CC from VRO Myths: ..Air leaks and/or fuel restrictions will affect the VRO and usually show up as excessive oil
consumption, smoking, and fouling plugs. If air gets into the fuel, it
causes a foamy solution, similar to a head of beer in a tall glass. ( A
vapor lock situation does the same thing ). The volume of liquid fuel is
less and the oil delivered is the same as for a full chamber of fuel. Now
you have richer gas oil mix with its resulting symptoms.
 
faztbullet said:
CC from VRO Myths: ..Air leaks and/or fuel restrictions will affect the VRO and usually show up as excessive oil
consumption, smoking, and fouling plugs. If air gets into the fuel, it
causes a foamy solution, similar to a head of beer in a tall glass. ( A
vapor lock situation does the same thing ). The volume of liquid fuel is
less and the oil delivered is the same as for a full chamber of fuel. Now
you have richer gas oil mix with its resulting symptoms.
Click to expand...
understand your explaination completely thankyou. going to install a clear hose on fuel inlet line at filter housing and watch for bubbles. if present will replace the fuel line from the tank to the filter and see how that works for smoking condition. your thoughts??? thanks bob
 
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