Mercruiser 5.0 question (1 Viewer)

[bsilva132]

I have a 94 Reinell (20') with a Mercruiser 5.0 Alpha One w/ Thunderbolt Ignition. ~450 to 500 hrs on engine, 2 barrel carb, just had a 100 hr service. For some reason it dies when you shift into reverse. If you slowly shift into rev and slowly give it gas it will sometimes revs up, but usually dies. Runs perfect going forward and ran perfect the first time we took it out this year. The problem started before the 100 hr service. I have a Seloc repair manual coming, but was wondering if anybody has any ideas as to what the problem is??? The throttle appears to be working properly but I only know enough to be dangerous.

Thanks,
Brian

 

[bsilva132]

ttt

 

[cruiserdan]

Perhaps a problem with the throttle linkage? The linkage is kinda wierd because it has to open the throttle in the same direction no matter which way you move the lever. Mine is a 4.3 with a 4 barrel but I have not personally had that problem with mine. You may have someone shift it for you while you watch the linkage (engine off) and see if you can spot anything that looks odd.

 

[Rugster]

The ignition natural interrupt switch might be acting up. It temperately interrupts the ignition to ease into gear.

 

[fourand20]

check out the tranny reverse gearing and clutch pack.....im guessing it is stalling out like a manual trany

 

[MJM]

Throttle Cable

Sounds like the the throttle cable need to be replaced, this happens to all of them over time. I bet when you do get it stay running in reverse it is at a high RPMs well atleast enough to turn some heads.

 

[bsilva132]

the throttle appears to be working correctely. It shifts into R fine, but when you give it gas it dies instead of throttling up. Too hot right now to mess with it. Thanks for the starting points. I will give an update when I get a chance.

 

[bsilva132]

Had a little time today to mess with the motor and it finally is under 100F when it is light out. I ran the engine (with a hose/rabbit ears on the intake). When I throttle up in rev w/o engaging the trany, it revs up fine. But when I throttle up w/ the trany engaged it dies. It will still run when you first shift into rev, but when you throttle past an idle it dies. I have a feeling I am just going to have to take it somewhere. Hopefully I can get it in somewhere in a reasonable amount of time. Last I heard, all of the boat maint businesses are booked up right now.

 

[bsilva132]

Fixed it myself. Between your guys suggestions, the Seloc manual, and a write up on www.boated.com (great tech section) I figured out it was the momentary interupt switch which was out of adjustment. Works perfectly now.
Thanks,
Brian