1995 Mariner 40hp Magnum won't idle

[Kyle C]

Hello everyone, I've got a 1995 40hp Mariner Magnum 4 cyl. 2 stroke motor that won't idle when cold and will idle for a few minutes after run for a while. It runs great at 1000 to 5500 rpms and I get a top speed of 25 smph on plane on a 16' Sea Squirt. I was wondering if it was a timing issue? I have replaced the stator and the trigger, rebuilt the carbs and replaced the spark plugs with NGKs (buhw-2). I have the manual and it says cranking timing is 32 deg. btdc. Am I correct in assuming that I should set it at that while turning the motor over? If so, I don't see 32 deg. while cranking the motor. Any help is, as always, greatly appreciated. Kyle

 

[CharlieB]

Re: 1995 Mariner 40hp Magnum won't idle

Do you have a FACTORY service manual?

You may have transposed those #'s, maybe should be more like 23, not 32.

Remove the spark plus, ground the wires, disconnect the throttle cable and use a zip tie or something to hold the throttle wide open, so that timing is at max. Attach your timing light and crank the motor while observing the flywheel for your timing marks.

Check your manual for specification what marks are used, some motors the pointer must be indexed, your manual will spell out in detail.

If no manual, check these sites to see if yours is available.

http://1manual.com/Mercury manuals/Service_Manual_Index.html

http://forums.iboats.com/showthread.php?t=309079&p=2072211#post2072211

 

[Kyle C]

Re: 1995 Mariner 40hp Magnum won't idle

It's the factory manual. It says maximum timing @ cranking speed 32* btdc. @ 5500 rpm 30* btdc. I've done what you suggested and the timing was close to 0*. Doesn't seem right. Thanks