merc 115 reeds

[izu]

when reeds are gone or going bad what are the signs or symptoms. If they need replacing is it a big job,would U take it on,is it worth it on a 1986 engine

 

[AMD Rules]

Re: merc 115 reeds

Usually, worn reeds will show up as an engine with an erratic idle. Worn reeds are more detectible at lower speeds, than high speeds.

A badly worn or broken reed, will typically cause fuel to be 'sneezed' out of the throat of the offending carb. ie. Crankcase pressure escapes through the void/gap left behind by the broken reed sending the fuel mixture with it.

Another sign of worn reeds, or bleed restrictors is an inability to achieve factory linkage adjustments, where you have had to compensate linkage adjutment to make up for worn/broken/missing components.

There may be other indicators I have not thought of.

 

[izu]

Re: merc 115 reeds

Thanks AMD Rules,I trust your feedback.I am not experiencing the conditions U described. Its cold here,still no power dies at @1500 rpm in forward gear on trailer at boat ramp. I've been told that idle maybe too lean by forum members I think the marina machanic is taking me for a slow expensive ride.I have replaced defective stator with a new one and also new PAC .its nolomger misfiring at all. Please advise, I bought a dva meter recently as reccomended by Laddies.

 

[Chris1956]

Re: merc 115 reeds

Isu, I know it is cold on the east coast, bt you can save this procedure for the spring if necessary. The spec on the idle adjustment is likely "Halfway between too lean and too rich". Since I was never able to determine that, by ear, here's how I tun my inline sixes. Remember gravity causes the mid and lower carbs to run a bit richer than the upper carb. Ditto on the cylinder pairs for each carb.

Set all carbs idle adjustment screws 1-1/2 turns CCW from lightly seated. Start and warm motor in water, in neutral. Adjust for best idle speed in neutral. Start adjusting the carbs, botton carb first, usually CW (lean), until you achieve the highest RPM and smoothest operation. The top carb will likely be set richest. Now try to accelerate, and the motor should either stall or stumble. Richen the top carb (CCW), and try to accelerate again. If it still stalls or stumbles, open the mid carb 1/8 turn and repeat. Always richen the lower carb least, the mid carb next least and the top carb the most. You are trying to achioeve as lean a mixture as possible and still have good acceleration. Eventually you will find an adjustment where the motor will idle OK and accelerate well. BTW use fresh premix gas, if motor is not injected.