1977 Mercury 1150 runs good in neutral put it in gear and it dies

[Jake_s22]

Hello guys, I just bought a boat and all I've done is work on it so far. When I hook it up to a hose it idles and revs up good and goes into gear and revs up good. When I go to the lake and put it in gear and try to rev it up it dies! If I slowly rev it up it will stay running at low rpm's. I've check compression and all cylinders are good and replaced all the spark plugs. Ran fresh gas threw it with sea foam. Adjusted carbs back and forth. What else should I do? Any help would be appreciated. Jake

 

[Texasmark]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

The lake imposes extra load on the engine that you don't have on muffs. Extra load means extra fuel. Rpms can be too low to sustain life. Something less than 1000, like 675 for my Merc is spec. in F gear in the water which translates to 800-900 in N on the muffs. Want it high enough to keep the engine running when you shift but not so high so as to cause shifting damage. So, I'd keep using the Sea Foam and increase your idle a bit. Then you can open your low speed jets 1/8 turn at a time if idle doesn't fix it.

Mark

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Thanks mark I have ran 7 gallons of gas threw the engine with sea foam and have adjusted the screws on the carbs and it doesn't seam to help. I took the lower carb off today and cleaned it and it looked pretty clean already. I'm stuck again. I don't know if I should go threw taking all the carbs off or put the bottom one back on and run even more sea foam threw it. Fuel pump screen is clean. Any other thoughts? Jake

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

jake, Are the floats and inlet and needle in good shape and adjusted properly? Set the idle mixture screws to 1-1/2 turns out from lightly seated. Now adjust idle needles for smoothest and fastest idle. Close the throttle if the idle speed is greater than 1200RPM, so it will be about 1000RPM or a bit less. Now do some water tests. try to accelerate from idle speed. If she stumbles or dies, open the top carb 1/8 turn and try again. open the mid carb 1/8 turn and retest. Open the bottom carb 1/8 turn and retest. See the pattern? Repeat, testing after each adjustment. Eventually you will get a resaonable idle and good acceleration.

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

The carbs look good I am going to put it all back together tomorrow and try to get it running right I will post what the results are good or bad I'm hoping for good I'm ready for this thing to start running like it should. Thanks for the help

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

I got the carbs all back on and filled a barrel full of water and started it up. It sounded a little rough so I adjusted the carb screws out an 1/8 at a time still sounds a lil rough. I'm thinking I might have a timing issue. ???????

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Timing is easy to check. But first warm up the motor and adjust the carbs for smootest running. After that you will need to water test it and adjust carbs for acceleration.

Set the timing pointer by using a dial indicator or accurate ruler thru the #1 apark plug hole. Add .464 to the measurement to the piston top and turn the flywheel CCW until you get that reading. Now set the timing pointer to the .464 mark on the flywheel decal. Now remove spark plugs 2-6, install them into their wires and ground their bases to the block. Advance the throttle until the carbs are ready to open. Timing should be 4-6* BTDC. Now push throttle full. Max timing shold be 21* BTDC.

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Well I took it to the lake and got it to plane out a couple times. I need to get a timing light so we can get it timed right. It was weird it would run fine for a lil bit and then it would die when I tried to rev it up the next time.

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Does this motor have CDI or points?

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

It has battery-powered CDI ignition with a hall-effect trigger in the distributor.

 

[wired247]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

It has battery-powered CDI ignition with a hall-effect trigger in the distributor.

Thats not a Hall effect sensor in there unless he changed to a CDI ( the company ) distributor. The Mercury units have Variable Reluctor pickups. If the amplifier ever craps out they can be replaced with 6 Cyl. GM HEI modules at a fraction of the cost.

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Could anything like that be causing my problems??

 

[wired247]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

If you can rev it up out of the water and get a good spark then it isnt an ignition problem. Wear good gloves and use fuse pulling piers and pull a boot off the plug and stick a screwdriver in it. See how much the spark will travel. Should be 7/16 inch or so. '

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Jake, I would not think so. You might check the spark plug leads to see if any are arcing to ground though.

Wired, He has a distributor ignition with the six-window trigger plate. It should be the same as on your '73 1500. I have always known it as a Hall-effect trigger. Normally a reluctor has lobes that trigger the amplifier, like on my '88 4.3LX MerCruiser

 

[wired247]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Jake, I would not think so. You might check the spark plug leads to see if any are arcing to ground though.

Wired, He has a distributor ignition with the six-window trigger plate. It should be the same as on your '73 1500. I have always known it as a Hall-effect trigger. Normally a reluctor has lobes that trigger the amplifier, like on my '88 4.3LX MerCruiser

Its VR. I did some research on mine when I was thinking about running with a MSD box. The replacement CDI units are hall effect but the originals are VR and can be amplified with a GM VR amplifier. Thats why if you use the original brass reluctor wheel the CDI unit will not work. The CDI unit is steel and blocks the magnets signal enough switch the hall effect transistor off when the solid plate rides in front of the pickup. I hooked an o-scope up to mine and it puts out that weird VR wave pulse.

Spin a CDI pickup unit and a stock distributor next to one another. Definite magnet pull on the CDI unit and the stock unit spins freely.

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Well I got a timing light today and the previous owners had it way out of time but it's timed now. The idle is too high though. I think I need to turn the carbs to the closed position? Or maybe there is another way. Thanks for all the help so far I'm so close to seeing this motors full potential!!!

 

[Texasmark]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Well I got a timing light today and the previous owners had it way out of time but it's timed now. The idle is too high though. I think I need to turn the carbs to the closed position? Or maybe there is another way. Thanks for all the help so far I'm so close to seeing this motors full potential!!!

Nowadays, the idle set screw sets the timing, has nothing to do with the carbs. Just look at the idle set screw and what moves when you move it and you will know. My engine is the newer design looper and the carbs are real tricky so they set them up to run the engine and use retarded timing to slow down the idle. If it runs the butterflies, can you back it off, thus closing off the air to obtain your desired idle, or are the butterflies fully closed. If so, and it does control the carb then you probably will have to shut down your low speed jets somewhat. Don't close them so much as to keep the engine from taking throttle in the hole shot.

HTH,

Mark

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Jake the idle speed is controlled by the idle stop screw and the throttle cable. Back down the idle stop set screw and adjust the throttle cable to push the throttle closed, to achieve the correct idle speed. After you set the idle stop screw, adjust the throttle cable to add some preload.

Wired, Are you sure you are talking about a 1977 Inline six Mercury Ignition System? Your terms for it's components are unfamilar to me and I owned one for 30 years..... Maybe your motor is mix-sixties with some other kind of ign system?

 

[Jake_s22]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Tried to turn the idle stop screw out a turn now it runs like crap again??? I'm lost I must be doing something wrong!

 

[Chris1956]

Re: 1977 Mercury 1150 runs good in neutral put it in gear and it dies

Idle stop screw is on a black bracket above the distributor. Is that what you were adjusting?