89 40hp mariner stalls

[dirtybrid]

i have a 89 40 hp mariner 2cylinder outboard...i have the air screw at 1.5turns out,timing set and carbs clean as can be and new plugs,compression at 125 both cylinders..ive had this problem for a year now and no shop has been able to pin point so mabey someone sould help me out...if you take off the engine cover the idle will raise and lower when putting back on...if left to idle will stall..seems like it loading with fuel because of the amount of smoke and the fact if i use the high idle and hold all the way up will rev like the plugs are fould then clear up and rev fine..i replace the plugs once a month due to the amount of use..also after makeing a run weather long or short at 1/2-3/4 throttle the idle will hang high and eventully come down..or if i kill the motor and restart the idle will drop..also sometimes after a run when put in neutral it will seem like it loading on fuel and stall..i have a feeling this is all going to be realated to this engine cowl affecting the idle but dont kno how to fix this...any help would be greatly appreciated..i use the boat 4 night a week for 3-7 hrs to flounder gig and after a year and two shops its gettn annoying with these issues..thx

 

[Ballymac]

Re: 89 40hp mariner stalls

Two things come to mind, the carb & your reeds. I?m assuming you have good gas at the correct ratio in a clean tank, through clean lines with a good primer bulb, through a good filter. I know you mention the carb is clean, has it been rebuilt? Clean is not rebuilt. Also, check the reeds for cracks and if they?re seating properly. Would be suprised if it's the cowl. Will it run differently in all stages mentioned if the cowl is off? Better across the board?

 

[dirtybrid]

Re: 89 40hp mariner stalls

i acutally found the issue..the exhaust doughnut on the lower unit was not around the exh port..the exhaust was comming out all around the muffler..that and the gaskt sealing the engine compartment not sealing thus letting exhaust smoke get in and choke the motor out with the cowl on...correct fix is to take the power head off and replace the gskt..my fix was clean the area and use rtv to seal the area off all the way around the lower part of the motor housing..also rtv the exhaust gaskt in the correct spot..took it out and no more stalling issue and the idle stayd the same reguard less of cowl on or off..but yes i have a new tank and all new lines..i try to keep the boat as clean as possible and in good running condition..but the carb was cleand not rebuilt..

 

[Ballymac]

Re: 89 40hp mariner stalls

Nice catch & good luck with her.