03' Merc 150 XR-6

**Charger_** · 05-16-2024, 06:49 PM

03' Merc 150 XR-6 carb engine ID#OT649715
CONTROLLER-IGN: Part# 857185T1

Maintenance: I replaced the Trigger (I marked it to put back in same location) and the IGN-Controller due to failing specs. Lubed shift/throttle cables.

Issues: When you initially start the engine it takes a few minutes then it sounds like you put it in gear but your in idle. Why is that? I thought the IGN will control the idle and makes its own adjustment.

Grinds shifting into reverse.

When you come down off throttle and return to back to neutral, it sounds like your still in gear.

Anyone have a service manual that supports XR-6 - 0G960500 THRU 1B226999

**tlwjkw** · 05-16-2024, 10:30 PM

send me an email addy and i'll send ya one in pdf.....................

**Charger_** · 05-18-2024, 06:43 AM

Any ideas / help on how to address these issues? Experience with this IGN-Controller to know how it works?

**tlwjkw** · 05-18-2024, 09:10 AM

90-878079 on ebay................

**OnPad** · 05-18-2024, 11:48 AM

Not exactly sure by what you mean when you say it sounds like it goes in, or out of gear? Is this a noticeable drop, or increase in rpm? Does this engine have a alternator?

I'm not very familiar with this newer stuff, but going by what I know about the earlier cdm engine. Which ain't much.
The ignition control module sends trigger signal to cdm's. It probably has a idle stabilizer, and a rev limiter built in. The idle stabilizer function likely has the ability to add timing to increase the idle speed, but not any way to subtract it. So if the idle timing is set too high, the engine is going to race at idle. This causes problems when trying to shift in, or out of gear.
The wiring diagram shows a shift switch. That has been known to cause some people headaches. I've deleted a few,... on older engines.

**tlwjkw** · 05-18-2024, 01:42 PM

Originally Posted by OnPad

Not exactly sure by what you mean when you say it sounds like it goes in, or out of gear? Is this a noticeable drop, or increase in rpm? Does this engine have a alternator?

think this would be one of those "ya gotta be there" sounds.... plain 'ole CDM motor.... no alt.

**Charger_** · 05-19-2024, 03:28 PM

It's an increase in RPM. Same when you go from forward back to neutral. Never quiets down it keeps wanting to race.

**OnPad** · 05-19-2024, 04:16 PM

Here's a pic of the idle timing screw. Clockwise is lower rpm. I told ya to turn that the wrong way in a pm a week ago. Sorry, good help is hard to find.
The larger adjuster screw under my thumb (pic 1) should be against the block at idle. When this screw is adjusted properly you should have a little play in the plastic cam, and roller (pic 2).