Shift/throttle - Maxum Boat Owners Club

Kpaul · 07-02-2022, 04:45 PM

I have a 1991 2500scr and am having trouble with the shift/throttle, it won’t engage forward or reverse but it will increase the revs, does anyone have any idea please?

Also, I don’t think the engine is drawing on water to cool the engine, I have had a battery issue and have replaced 1 battery, could it be the second battery that is causing the issue if it’s completely out of charge?

New owner and haven’t had one of these before so sorry for stupid questions!

Thanks,
Paul

mmwjr · 07-02-2022, 11:30 PM

Paul you issues don’t have anything to do with the batteries. Is the boat in the water or are you testing it on a trailer. Why don’t you think it’s drawing in water? Overheating, no water coming out the exhaust,...? On the throttle control is the center button not depressed. Back on the starboard side of the engine you will find the shift bracket where the upper cable from the control terminates and the lower shift cable to the drive is connected. Try removing the lower cable and shift it manually by pushing in and pulling out to see if forward and reverse engage. Can you post some pictures of the control and shift bracket? What engine and drive do you have? Manuals for both can be found under Documents.

Kpaul · 07-03-2022, 07:06 AM

Thanks for the reply,

Me water is circulating around the engine so it’s overheating.

I’m told it’s a 5ltr vivo penta engine, I’ll get some pictures and post them so you can see the set up,

Thanks

Kpaul · 07-03-2022, 07:07 AM

Not the best picture!

mmwjr · 07-03-2022, 11:20 AM

Maxim only used Mercruiser and I can confirm it is as I see the Mercruiser Thunderbolt IV module on the port riser. Not sure if it’s a 5.0 or 5.7 as they look the same.

You didn’t tell me if you are testing it in the water or on land. If land are you supplying water with a hose and muffs to the outdrive? Also do you have a Alpha or Bravo drive?

Kpaul · 07-03-2022, 12:51 PM

Sorry, it’s in the water and all the inlet valves are open.

It’s a 5.0 engine, I’m not sure of the make of the throttle, The handle is quite worn and I can’t see a makers name anywhere.

Sorry I don’t understand the Alpha/Bravo question.

Kpaul · 07-03-2022, 01:57 PM

First picture is in neutral, second picture is in forward and third picture is in reverse but gears not engaging.

Also a picture of the shifter.

mmwjr · 07-03-2022, 04:58 PM

Find the water hose at the inner transom plate and follow it. It will either go to a raw water pump on the lower starboard side of the engine or directly to the power steering cooler then the thermostat housing. Where it attaches to the thermostat housing try removing it and start the engine to see if water is flowing. No flow the impeller is shot. Regarding the shifting try disconnecting the end of the black cable in your picture. Start the engine and keep it at idle rpm. Now pull on the end of the disconnected cable, does it go into gear? Then try pushing it in all the way, got forward? The control is the US Marine design which is one of the cheapest controls made.

donald · 07-03-2022, 09:44 PM

Quote:

Originally Posted by mmwjr

Maxim only used Mercruiser and I can confirm it is as I see the Mercruiser Thunderbolt IV module on the port riser. Not sure if it’s a 5.0 or 5.7 as they look the same.

You didn’t tell me if you are testing it in the water or on land. If land are you supplying water with a hose and muffs to the outdrive? Also do you have a Alpha or Bravo drive?

Mike it looks to me that it is a A1, can not see belt driven water pump in photo.
Definitely is an older model as it has older style valve covers.
Don

mmwjr · 07-04-2022, 01:02 AM

Quote:

Originally Posted by donald

Mike it looks to me that it is a A1, can not see belt driven water pump in photo.
Definitely is an older model as it has older style valve covers.
Don

I suspect so to Don but B2’s were available then on this size boat and a clearer picture will confirm.

Kpaul · 07-04-2022, 07:16 AM

Thanks guys, I will take some better pictures today.

I appreciate all the help.

Paul

Kpaul · 07-03-2022, 05:15 PM

Can I just change the control or do I need to replace everything?

mmwjr · 07-03-2022, 05:29 PM

Quote:

Originally Posted by Kpaul

Can I just change the control or do I need to replace everything?

I don’t know if the existing cables will work on the new control. I recommend either a Quicksilver or Teleflex replacement.

mmwjr · 07-03-2022, 05:31 PM

A picture of the front of the engine would also be helpful. Basically I’m looking to see if you have a raw pump on the lower starboard side that driven by a belt. If so you have a Bravo drive if not it’s an Alpha. Under Documents of this site you will find the Mercruiser manuals for your engine and drive.

mmwjr · 07-06-2022, 05:14 PM

Yes, that’s the one!

Kpaul · 07-09-2022, 08:34 PM

Hi, I removed the pipe and water is coming out when the engine is running, I’ve also noticed that the oil filler cap is loose, will that make a difference?

mmwjr · 07-09-2022, 10:34 PM

Water coming out of this hose verifies the raw water pump is working so why don’t you think the engine is cooling? I would use a handheld IR sensor and take temperature readings of the thermostat housing and exhaust manifolds/risers. Other than making a oily film on the engine a loose cap shouldn’t cause any issues.

Kpaul · 07-10-2022, 06:00 AM

When the boat is at sea, the temperature rises very quickly under pressure and a lot of smoke is coming out, it then cuts out and will sometimes start and other times it won’t.

This happens within probably 15 minutes, the time it takes for us to get out of the marina into open water.

Oil levels and pressures are all ok though.

mmwjr · 07-10-2022, 11:52 AM

Ok get the Mercruiser manual under Documents and perform the water flow rate test on the same hose you removed before to be sure it’s pushing the right amount of water. Then remove the water hoses to each riser to check water flow. Finally remove the exhaust risers to inspect the water passages for blockage.