6.2 Mercruiser stall shifting gears
 

I have a 2002 6.2 Mercruiser that wants to stall while shifting into forward or reverse gear. When you go to make the shift the idle drops and it stalls out. Whats up with this? Think I herd of someone else having this problem years back on a old 70's Mercruiser and it was the shift intrupter switch or something like that. If you think this is my problem where is it located and how hard to fix. Is it a do it yourself type of job?

Alpha or bravo? if alpha its time to do the shift cables.

Definately agree if an Alpha.

6.2 should have a Bravo...so something engine related like IAC or something. And for some reason most people never clean the flame arrestor.

if it is an alpha, look at the bracket mounted on the right exhaust manifold with the 2 shift cables on it. the interrupter switch is right between the 2 cables. the switch is fine. lower cable is tight and won't let interrupt cable snap back to center. the interrupter is to shut off ignition for a split second to take load off drive so it can come out of gear. the tight cable makes the switch cut ign every time you shift. you will probably see the switch activate even when shifting with engine off which is a sure sign cable is shot.

Bravo one

Shifting a bravo with the engine not running is a big NO NO

I do believe its the AIC as well because the engine surges a lot aswell. I went to get one and it was like 306.00 plus tax but I read somewhere you can get them for cars at a much cheaper price!! Anyone know what car??

496ho did this last season - IAC sensor fixed it

If anyone has a picture of this part and Knows what Make/Model/year/ Car or truck I can get this part from?? This would be great!!

Check to seewhat part # your's is
www.Mercruiserparts.com

Then see if same as the 496's.

If so, do a search here, it's a Ford Part. Windstar or something.

BAM has your IAC for $138. Also see 2 new ones on Ebay for $90. Just need to look around. I bought a Car one equivalent one time. It hooked up great but was clocked wrong and my cable wasn't long enough to make work without major modification......JFYI

Before you do anything here -- you need to list your engine serial as your 6.2 might be possible MEFI 3 and that GM IAC was not the problem like the ford IAC using Motorola ECM 555 was.

Also there is service bulletins that are linked per engine serial numbers. Some related shifting problems as well.

I preached this for 5 years straight up here that everything marine related goes by serial numbers

1. it shows what one exactly has
2. it shows what set ups and proper parts from the OEM factory that the engine has installed per serial numbers ranges
3. certain service bulletins go with per serial ranges along with recalls and federal recalls
4. Proper service procedures and service material go with per serial ranges/
5. Updated part changes
6. and more why serial numbers are so important.

That sucks because I just put a new IAC sensor in yesterday and plan on taking the boat out tomorrow! I also bought a spare one in case I run into this problem again as my research on the internet indicates these are problematic and I should carry a spare. The engine surged and stalled shifting and this seems to be the fix as per whats said on the net. The one I purchased was for a 2002 Chevy Blazer.It does look the exact same as the one I pulled off.... hope this works!! So what do I need to change if this don't work??

Okay, you have a different serial # 6.2 than we where thinking. As BUP said, we needed to know exactly what we are dealing with.

Your IAC is Merc #803149 and looks like below pic ?
If so this should be the ACDelco part:
ACDelco 217-435 GM Original Equipment Fuel Injection Idle Air Control Valve
by ACDelco
Link: http://a.co/7bRgBRT
http://www.mercruiserparts.com/conte...03149_550.jpeg

Yes it looks exactly like that one. And the replacement looked exact as well...am I ok??

They IAC are NOT interchangeable from MEFI 3 to ECM 555.

To let you even know further YOU NEED TO POST your serial number to get correct help.

The 6.2 from merc was done 4 different ways - even Merc racing had a 6.2.

There is also a Black Scorpion 6.2

some engine serial numbers MEFI 3 -- 6.2 even used a fuel pressure sensor.

Like I said many had SB's per engine serial runs and few where about shifting / engine running problems.

The GM IAC was far less a problem than other IAC merc set ups.

The TPS for these earlier versions was more of a problem than the IAC. Not saying you could nt have a IAC problem but my main POINT here is sometime the net can help but how can one reply a fixed when they really do not even know what you have nor its set up nor the correct parts used. That is dart throwing and wasting money totally as being a parts changing keeping fingers crossed ---"is this going to be the part that fixes my boat " .

Just posting SOLID info. that's all and your serial number is really needed -- can care less what the replies are until then. Yes lucky guesses do happen as well for fixing anything. Good luck and who knows maybe a new IAC fixes your problem.

A scan of the engine while running and shifting would help possible pin point the problem as well.

sure but was it installed correctly and set correctly after changed ? Was it a quality brand ? did you have power completely off when you removed and replace your connections ? Did you scan the engine and see where your IAC count parameters at while engine running and shifting ?

0m072864

Sounds like I need to take the boat to a Merc Tech. I don't have the scanners and tools obviously needed. Things I have read on the internet make it sound like you just need to swap them out. I don't know anyone who carries these tools and scanner out on the lake . this is complex stuff Guess and carring an extra as iv read over and over does no good without the tools and scanners

Just so you know BUP's terminilogy, SB = Service Bulletin.

I know, it always looks like he is referencing me, but he is not. LOL. :)

I ran your serial # at Genuine Mercury & Mercruiser parts and it is the one.
As BUP states many times, OE is the way to go on all electronic parts (i've been in auto repair since the dinosaurs disappeared) unless it is proven an aftermarket has a better design (rare!) for any part in question.

So, thus why I checked ACDelco as they are the OE manufacturer/supplier on these IAC's. Merc uses many GM parts in many of their motor assemblies for obvious reasons.

I will add that Mercruiser Makes its own T bolt IV / V distributor cap and ignition sensor right here in the USA. They make these parts and some others right in florida. Merc makes other electronics and plastic parts as well. Just and FYI

All the other ignition sensors on the market come from Taiwan and other marine ignition parts