Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

[colburn3]

BAD NEWS ON A WEEKEND...

So yesterday I was skipping across the lake back to the marina. Everything was humming along beautifully (96' 250CR Crownline) at 3800RPM's. All of the sudden I lost plane and the RPM's went down to 2000RPM's. The throttle seemed to be sticking and I couldn't get it back into neutral. I shut the engine down and investigated it but nothing was glaringly obvious. I was able to re-start the engine and get it into nuetral but when I tried to shift back into forward or reverse the gears would not engage. After a couple times of attempting to shift into F / R the throttle seemed to get stuck and would be almost impossible to move.

It seems to me that the throttle cable is damaged and my questions are as follows...

1) What can cause a problem like this?
2) What are the steps in trouble shooting to find the exact cause?
3) Could this turn out to be more damage than I am envisioning?
4) What are the typical costs to solve this problem
5) Could I have forseen this somehow / did I overlook a glaring sign of wear?

Thank you in advance for your help! We've been getting some amazing days out here on Lake St. Clair (MI) and I don't want her to be shut down for a very long time.

Thanks Again!

Justin
96' 250CR Crownline
Lake St. Clair, MI

 

[dubs283]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

your first step is to remove the cables that come from the remote at the engine, one for throttle, the other for shift - the shift cable will be the top one on the shift plate assy

then see how easily the throttle/shift lever moves at the helm with out running the engine

if the shift/throttle handle still moves difficult, your problem is in the remote control or more likely one or both of the cables

if the handle moves freely, the issue is either the lower shift cable or drive related, your 1996 7.4L engine is more than likely coupled to a bravo drive, yes??

 

[colburn3]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

Thanks for the reply!

Yes I have a bravo II outdrive.

So in the engine capartment I will find the shift / throttle assembly bracket. I should remove the two cables that are on the bracket. How do I go about doing that? I don't want to start tearing things apart unless I fully understand what I am doing. Are these just simple screws?

Once these cables are apart (any more description on removing them would be great) I should move the throttle back and forth.

1) If it is difficult than my problem may be the remote control (I'm unfamiliar with this can you please be a little more descriptive)? What would be entailed if this was the issue?

2) If it is easy to move than the issue could be the lower shift cable. Where is this and how would I know?

You mention a drive issue could also be the problem. That sounds scarier than a simple throttle cable replacement. Any idea as to what that could possibly entail?

Dubs283, I really appreciate you taking the time to shed some light on a newbie boater.

Thanks!
Jc

 

[Bt Doctur]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

most times when you overheat you fuse the lower shift cable solid ,throttle cables on/near the exaust system will do the same thing. disconnet the throttle cable at the carb ot throttle body, and test. do the sane for the shift cable .there usually mounted on the stbd riser.

 

[colburn3]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

"most times when you overheat you fuse the lower shift cable solid ,throttle cables on/near the exaust system will do the same thing. disconnet the throttle cable at the carb ot throttle body, and test. do the sane for the shift cable .there usually mounted on the stbd riser."

Thanks for your input BT!

Just so I understand, you're saying that when I overheat (is this a typical senerio durning normal operation or when the engine shuts down from overheating) the cables will literally 'melt' together causing my inablility to operate the shift / throttle unit?

So I can disassemble the throttle linkage at the carb unit and at the starboard shift bracket. What would be concidered a good / bad test once I do this?

Thanks again, I'm nervous this is bigger than a simple cable swap.

 

[Bt Doctur]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

once unhooked, the control box should work normally,and free. test the carb/throttle body by moving the arm .then try the lower shift cable

 

[colburn3]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

Okay, I just got back from the marina and did some trouble shooting.

I was able to jiggle the throttle after much effort and got it into nuetral. I then started the engine and let it warm up. I was in the slip and just wanted to bump into gear (F & R).

I was able to shift into F & R and hear the gear drop into both positions. I was able to slowly push the boat forward & reverse, basically didn't want to do anything beyond that.

It seems like the throttle / remote control is getting bound up. Do these things tend to go (96' original) or does this still seem like a throttle / shift cable issue?

 

[dubs283]

Re: Merc 7.4L 454 Throttle Stuck & Won't Engage Into Gear

the only way to determine if it is a cable issue or a control box issue is to remove the cable(s) at the engine and try the remote control (like stated in previous posts)