1974 Mercury 1150 has new rectifier/stator and now won't idle

[Chris1956]

It is normal for that timing to look to be 1/2 tooth off, and it makes a difference, which way it is off, that 1/2 tooth. If it runs better, you should be good to go. If you want to verify timing, remove spark plugs 2-6, stick them into their wires and ground them to the block. Set the throttle to the position where it just touches the carbs, and the carbs are about to open. Install a timing light on the top cylinder. Jumper the starter solenoid (motor in gear, prop removed), to crank the motor. Timing should between 4 and 6 degrees BTDC. Now advance throttle fully. Crank motor and observe timing. Timing should be 21* BTDC. If it differs from that, you probably should get a service manual and reset it.

 

[bassboy416]

thank you for all your help. I believe my timing belt might be too loose. Went out today and it ran different than usual but had way more pickup from idle to full throttle. It fired up and idled great. Ran fantastic. It has always bogged when hit full throttle from barely in gear. Today it was on top of it. Pulled my large body on a wakeboard and had a great day then at the end of a long run it bogged out. I thought I was out of fuel so I added fuel to the tank. Was difficult to restart but started again. It would run but would not get on plane... basically nothing above half throttle. Looks like it jumped a tooth in the opposite direction. Time for a new timing belt?

 

[Chris1956]

Gee, they should not jump teeth. There is no tension adjustment on the belt. Inspect the teeth and see if they are worn, or the belt is stretched. I would think 1/4" deflection on the belt would be acceptable. They are not real tight.

Replace if necessary. Also spin the distributor when you have the belt off ad see if she moves smoothly. If that bearing is going bad, it will stress the belt.

 

[bassboy416]

Definitely more than 1/4 inch deflection. Its more like 1/2 inch seems pretty loose but whats weird is it seemed like it jumped the opposite direction as last time. It just died out at WOT and then wouldn't get on plane after that. In nuetral it revs up just fine but under load it just won't get to top speed anymore. Fuel pressure guage is reading 5psi. It usually reads 8 at WOT. But if it was fuel related wouldn't it be unable to rev in nuetral? Is it possible it jumped a tooth in the opposite direction? Should I just sink it and start over?

 

[mr 88]

Maybe try opening your idle screws a hair. Engine will rev all day in neutral ,no load . The transistion circuit is very poor in those carbs and they need a bit more fuel to go from slow to fast.

 

[bassboy416]

I might try it but I am hesitant to change any more settings. The carbs were tuned well and it ran well 2 weeks ago. I changed stator and rectifier and then it wouldn't idle right so I investigated timing and changed it. Now it has a totally different issue. I might have a loose timing belt, but I am afraid to monkey with any other settings as I am afraid I might have already damaged something by changing the timing. Is it possible that several unrelated random issues are all happening at once? what would happen if the timing belt were too loose? Would it even be possible to be jumping timing in both directions? could my carb need adjusting just because of a new stator or timing setup?

 

[Chris1956]

I recommend you get the timing squared away first. Remove the cover on the distributor pulley. At TDC the cast arrow on the dist. pulley should point at the dot (or 3 dots) on the timing decal on the flywheel. At this point inspect the timing belt for rounded teeth on the belt, cracks etc. If in doubt, pull the outer flywheel (eight 5/16" bolts) and replace the belt. Before installing the new belt, spin the distributor pulley and wiggle it to check the bearing. There should be no play and it should move smoothly. Now reassemble everything and check idle pickup and max spark advance timing.

 

[bassboy416]

Thank you chris 1956. You have really helped me throughout this process. I will thoroughly read the timing and syncronization section of the manual and check the timing with a light before moving forward. I can't tell you how much I appreciate your help.

 

[Chris1956]

BB - no sweat. Glad I could help. The only tricky thing about the synchronization is the idle pickup timing adjustment. There is a brass colored collar with plastic covered fingers that advances the distributor. This collar must rotate to adjust the timing. There are two stainless steel bolts that tighten the collar to the distributor body. You need a 5/16" open end wrench to loosen them. They are under the distributor body "lip". The manual is a bit vague on that point.
Best of luck.

 

[bassboy416]

Compression test showed number 1 spark plug to have what looked like molten aluminum on it (ill post pics) and no compression readings would build. It would go up on the guage and then leak out to zero. checked guage and its not the guage. cylinder 1 also seemed to have half the compression as the rest but was impossible to get readings with the leaking to zero. Anyone know a good salvage yard?