Mercury 120XR - Sand possibly sucked in by jet pump?

ctniedermair

Recruit
Joined
Aug 10, 2011
Messages
1
Hello everyone. First post on this forum.

I have a 1997 120XR Sortjet engine in a Bayliner Jazz that I just started having trouble with. I bought the boat in Spring and have had it out a couple times a week since and always ran great.

A week ago I noticed a small amount of smoke from the engine compartment after returning home from a half hour trip up river. Launched the boat a couple days later and noticed there was some hesitation accelerating and I wasn't reaching the top speed I usually see. Noticed some more smoke coming from engine compartment. I opened the engine compartment. I could get high rev's from the engine but no propulsion so I shut it down.

I found and read through the sevice manual for the engine and think I narrowed it down to what's causing the problem, but not sure my best solution.

I pulled the boat up on the river bank to camp for a night before I first witnessed any problems. The engine was running in fairly shallow water and possibly sucked sand into the jet pump.

1.Should I purchase a kit to flush the cooling system?
2.Should I take apart the jet pump and look at the impeller?

I also noticed there was about 2"of water in the bottom of the engine compartment. I drained it through the valve in the floor. Not too sure how I ended up with that much water in there since I was only out a short while.

Last question.... Engine Serial #0E249047 / Pump Serial 0E51690 / When looking for parts I noticed there are 3 model numbers of this 1997 120XR Sportjet. Can anyone tell me the difference or where I could find this on the engine.

TIA for any help. First boat I've owned, don't mind working on it but would like to pull apart as few parts as necessary.

Conan
 

calledinsick

Petty Officer 2nd Class
Joined
Jul 13, 2010
Messages
160
Re: Mercury 120XR - Sand possibly sucked in by jet pump?

Look under the boat at the intake grate. Make sure there is nothing (not a leaf or piece of water folliage or anything else on/around/in it). Use a flashlight and look up through the grate at the shaft/impeller. Make sure it is clear too. Also verify the ride plate (around the intake grate) is flush with the bottom of the boat. If the edge towards the front of the boat is bent down (sign of starting out of water) at all or pieces of the foam seal are missing you will loose performance. Put the shifter in forward (raise the reverse gate) and look at the impeller/stator. Make sure it is clear of obstructions. Make sure the reverse gate clears the output nozzle while in forward.

I don't think the jazz should be taking on water. The older Tracker boats are riveted and tend to have some 'seepage' and water in the bilge is common.

With water and smoke in the engine compartment, I'd think about looking at the exhaust manifold. You may find that at idle (**Don't run the engine out of water**) it looks ok, but if you check it while at throttle you may find a leak. I've seen this a number of times. Sand/Gravel can cause serious issues in these engines.
 
Top