1995 Mirage Won't Start

[rjhart]

I just picked up a 1995 Mirage for cheap. Previous owner said it has not run in 2 years. It does not seem to be sucking fuel. I emptied the lines, cranked the engine, and watched the filter. No new gas was sucked in. As I understand, these 2-stroke Mercury engines have onboard fuel pumps, right? If so, how do I go about finding a replacement pump and then installing it?

I am no stranger to wrenching on vehicles, but I am on boats.

 

[Bilmon]

I have no hands on experience with the 90/120 motor but I do know they use a diaphragm type pump like all the Merc's. This should be the manual for the motor you likely have. Boatinfo - Mercury Service Manual for 90-120hp SportJet

 

[Stomp10]

Welcome @rjhart and congrats on your new to you Mirage.
There are quite a few of us Sugar Sand owners here who are dedicated to their boats for the long haul, for better or worse. Myself included.
Please keep us posted here as to how you are getting on in your restoration, ask any question. This community will do everything we can to ensure your success. And it's all free! You have come to the right place!
P.S. We love pictures too!

 

[rjhart]

Hey guys! Thanks for the great information and the warm welcome! That manual is going to come in handy!

I got the boat running and took it out on the lake today. The motor seems to be doing okay, but the boat doesn't get very fast and it won't plane out. I'm going to try to get a tach to see if this is engine related or see if it's related to the jet system. The plate under the boat does not seem to be bent. Any ideas what might be causing this?

 

[Blkrvrbart]

Welcome RJ. My first suspicion, since you had fuel problems to start with, would be fuel starvation. Fuel pump, filter, carbs, then go from there.

 

[rjhart]

Welcome RJ. My first suspicion, since you had fuel problems to start with, would be fuel starvation. Fuel pump, filter, carbs, then go from there.

I've already tinkered with the fuel lines and put a brand new fuel filter in. Unless the filter is too restrictive, I don't think that's the problem. The pump and the carbs are another story.

This is my action plan:

1. Change all spark plugs and wires, just to be safe.
2. Run a can of Seafoam through the motor
3. Check RPM
   1. If hitting full RPM, switch focus to the jet drive
   2. If not hitting hitting full RPM, focus on carbs and fuel pump

I am a bit wary to mess with the carbs; I am young enough that everything I've ever worked on has been fuel injected. But I suppose that now could be a good time to learn.

 

[Blkrvrbart]

I’ve not used Seafoam in a two stroke. So I can’t speak to that. But the plugs and wires, you betcha. That’s a good start. The carbs are really simple, you can download the manual from this forum to walk you right through the rebuild. Keep us posted!

 

[rjhart]

Some updates:

I changed the plugs and ran Seafoam through the engine. The motor sounds better than it did and the wake is more significant, but it goes no faster than 8 miles-per-hour (GPS verified as the speedometer doesn't work) and it still doesn't plane out. I checked the RPM and it got up to around 5,000, and I checked the compression and got between 105-115 PSI on all cylinders. I am starting to suspect that while the engine can still use some tuning. I am starting to think that the jet drive is to blame.

Here is a video of what it is doing:

Any suggestions or input?

 

[Stomp10]

To me it sounds like its still bogging down. Did you change the wires too?
If so, I would be inclined to be looking at fuel delivery after checking the drive components.
Look for gapped gaskets around the hull connection to the drive, check the impeller for excessive wear\damage and too much wear on the wear ring. The gap between the impeller vanes and the wear ring is very tight. I don't know the tolerance but its thousandths of an inch.
Any ropes get sucked up into the drive?

All that checks good then focus on fuel and the cdi units.
Maybe a spark tester on each cylinder will help with that, No personal experience with these for me yet. Never tried it on mine.

Wait and see what others have to say too.

 

[Chuck Buck]

Welcome, RJ! There’s some really decent, helpful folks here, so you’re in the right place. I’ll offer my 2₵ on your issues, but *Disclaimer* there are others with infinitely more 2-stroke Merc experience. If you have time to read my posts, I detailed my trials and tribulations with my 175 SportJet. First, Seafoam can be a miracle cure - I have personal experience with about 10 engines that were immensely helped by it. No wonder yours ran slightly better afterward, but my observation is that while 5000 rpm maybe near the WOT spec (I’m guessing), the video showed very little jet-wash. (BTW, the video was a GREAT idea.)

As they say – with jets, too low engine rpm @ WOT indicates engine problems, too high rpm @ WOT indicates impeller/wear ring problems. I think you have a combination of both; I think the impeller/wear ring clearance is allowing the motor to rev up, but producing little thrust. I think if the clearance were in spec, your engine would not get anywhere near 5000 rpm. I’d investigate the jet drive first and correct anything excessively worn, then see what your WOT rpm is.

AFA the engine - don’t rule out some knuckle-dragger previously bollixing something simple or obvious. A crossed wire, a critical adjustment, even an incorrect part installed. You’re going to have to do serious detective work and leave no stone unturned. However, in the end, you’ll have great satisfaction knowing YOU fixed it and you’ll know your boat so much better than just an “operator.” Best wishes!

 

[rjhart]

Wow guys, thanks so much for the information! I appreciate it.

I am going to get it back on the water soon (when the weather decides to cooperate) and use a better, more accurate tachometer. That will give me a better idea of what's going on with the engine.

In the meantime, I have taken the jet assembly apart. Here is a photo of the impeller:

Can I get some input on how this looks? I am going to check clearances with feeler gauges soon!

 

[Chuck Buck]

Yikes! From the looks of your pic, you need a yardstick, not a feeler gauge!

 

[rjhart]

Yikes! From the looks of your pic, you need a yardstick, not a feeler gauge!

Haha! I was thinking that the gaps were way too big, but I didn't want to influence what others thought. Where do I go from here? Should I replace the impeller and the wear ring? If so, where is the best place to source these parts without breaking the bank?

I know that JB weld can be used to fix the wear ring, but I am NOT good at doing things like that.

 

[Chuck Buck]

First, you need to remove the impeller to inspect the front of it and allow removal of the wear ring. There's good how-to instructions floating around on this site for that. Anyway, if the impeller isn't damaged, just worn, and the stator vanes aren't damaged or badly worn, I'd try the JB Weld trick. It's "quick and dirty" and you can't hurt anything at this point.

Now, if you really don't want to screw with it, or time is more precious than cashish, there's numerous companies out there that will fix all three. I haven't had experience with any of them, so I couldn't recommend any. Perhaps someone else here can help with that. @Bilmon ?

 

[Stomp10]

Well, I pulled my stator off last fall and I was thrilled to find new components in my drive although, I'm really not too enchanted with all of the corrosion on the wear ring. Also the deteriorated cable boots need replacing too. But this gives you an idea of how it should look, minus all that nasty corrosion:



A great resource you will need is:

Mercury Marine - A Worldwide Leader in Marine Propulsion | Mercury Marine

Manufacturers of outboard motors and MerCruiser inboard engines, with over 4000 dealers in the United States.

www.mercurymarine.com

You have to launch the catalog from that page but all your jet model parts are listed and it will also show availability.
Don't be discouraged though, oftentimes this becomes a labor of love.
If I were in your position, I would try jbweld on the wear ring, get it all back together again and see how it runs after.
The JBweld will buy you a season on the water and give you time to source parts. (probably) Also probably more work than you were expecting but it should be an inexpensive fix.
The parts catalog will give you part numbers. Usually just putting the part number in a search window will bring up whatever you're looking for.

 

[rjhart]

Thanks guys! I am going to be taking the impeller off next weekend when it's not raining, and I will be able to better inspect things from there. I will try to post as many photos as possible so that you guys can better assist me.

@Chuck Buck : There seems to be a company in Washington State that will bore out the wear ring and put a replaceable sleeve in it. I am strongly considering sending my wear ring out there later on, but will probably try the JB Weld trick to see if it will get me through the summer. Here is the website of the folks doing that: Sport Jet

Let me know what you guys think about that VS just getting a new wear ring.


@Stomp10 : That photo will be great for reference and the catalogue will absolutely come in handy! Thank you!

 

[rjhart]

Okay, so I have some updates:

It turns out that there was a screw missing on the ride plate. I imagine that this is I am going to obviously replace the screw. The rubber seal looks a little worn too, so I am going to replace that as well.

There is somebody selling an entire lower unit in good shape for a great price. I am planning on picking it up on Tuesday, after the holiday. I will transfer a bunch of parts and hopefully my problems with the lower unit will be solved.

 

[Bilmon]

That ride plate seal is critical, if it is leaking air and creating turbulence that can have a huge impact.

 

[rjhart]

I have decided that it would be best to replace the jet drive in my boat with the one that I picked up. The new one is in much better shape, it seems. Does anybody have any tips? I have all the motor and jet drive bolts removed. I am just struggling to get the jet drive out.

I know you are supposed to remove the powerhead completely from the boat, but I want to avoid that if possible. I've lifted it a couple inches to no avail.

 

[Stomp10]

Not sure exactly on the 120 but here are photos from my 175 manual on pump removal. Should be similar procedure for yours too, esp the sliding the boat back and supporting the hull in order to get the pump out.
Haven't searched on youtube yet but maybe something that may help you out.
seems like mercury Jet info is hard to come by there.



Good Luck and let us know how you get on.