What next? 90 hp Mariner

[zonaman]

I've got a 1995 Mariner 2 stroke (serial number 0G242454). I was at the lake and was starting fine and running well. Then it wouldn't start as if kill switch was pulled (it wasn't). It has spark to all 3 cylinders. I can pump gas through fuel pump and past filter up to carbs using primer bulb. I noted that when I partially unscrewed the top 2 carb bowl drain screws, no fuel came out. There was about 1 gallon of 6 month old Stabil ethenol gas treated fuel in the tank along 8 gallons of fresh, treated fuel. Didn't detect water in fuel as far as I can tell. Should I be looking at my fuel pump (photo attached) on this and, if so, how do I test it? Should I be looking at something else? Thanks in advance for advice.

 

[zonaman]

Update: Removed fuel line at carb (post fuel filter). Was able to get fuel to pulse out after priming and cranking. Engine running at idle. Note fine, black sediment in fuel. Again, What next to diagnose what the issue is or was?

 

[elsaylor]

is that fuel line breaking down? it looks like when a rubber line is giving up

 

[zonaman]

is that fuel line breaking down? it looks like when a rubber line is giving up

Seems possible- Particles like that ought not get past the filter. Perhaps from the friction of twisting off the line? New lines and filter are going in no matter what this is, since I've no idea how old they are.

 

[Chris1956]

So no gas from the carbs when pumping primer? That would indicate stuck float valves. Also, those particles can easily clog carbs.

So if they came from the carb, it is time for cleaning and rebuild and new fuel line and filter.

 

[zonaman]

That seems right but shouldn't the no start condition have persisted? Or can dirty carbs cause intermittent no starting?

 

[Chris1956]

Your post said it run and then died and wouldn't restart. That is consistent with carbs becoming clogged, as junk is sucked into the carbs. Did I read it wrong?

 

[zonaman]

Your post said it run and then died and wouldn't restart. That is consistent with carbs becoming clogged, as junk is sucked into the carbs. Did I read it wrong?

Perhaps and thank you for the reply. Rather than "run and died" it ran well then would not start. After I got it home and removed the fuel line at carbs and was able to prime fuel through (discovered sediment). I reconnected and have been able to start and idle the motor since. I noted that fuel pumps through when cranking as well. So I was wondering- Once clogged, always clogged? Hence a no start condition until serviced? Or is it possible that carbs can be fouled and still permit starting and idling? I suppose it's academic since I will replace the fuel lines and filters and clean the carbs in any case. Just wondering if it could be the fuel pump diaphragm that may be the culprit.

 

[racerone]

Cheap to replace pump diaphragm.-----Test operation of the enrichment solenoid valve.

 

[zonaman]

Cheap to replace pump diaphragm.-----Test operation of the enrichment solenoid valve.

I will. I'm still waiting for my shop manual to arrive; what is the procedure for this test? Thanks

 

[Briseno09]

I will. I'm still waiting for my shop manual to arrive; what is the procedure for this test? Thanks

I had a very similar situation. I was running at WOT, then slowed down entering the no wake zone and the engine just died. I would turn the key, engine would try to start but wouldn't. I had to get towed in. Once I trimmed the engine up to get it out of the water, the carbs drained. Got home and it started right back up. For me, seems like the carbs flooded. My mechanic buddy said it could be the pump diaphragm and/or carbs. Instead of second guessing, I rebuilt the 3 carbs, changed the fuel filter, changed the sparks, replaced the diaphragm(on removal, i noticed that the way it was set up, one of the gaskets was completely out of order that was provided in the replacement manual so i think this was one of my problems), and changed the temp sensor(getting a constant, non-stop alarm, thought the temp sensor would fix it). I could honestly say that the engine sounds as healthy as i've ever heard it and due for a trial run this weekend. I'd be able to provide an update as to if the above fixed my issue or not.

For you, I'd go ahead and rebuild the carbs and ensure the floats are adjusted to spec. The debris may clogged your carbs. Diaphragm swap is inexpensive and if you've never done it, it wouldn't hurt.

 

[zonaman]

I had a very similar situation. I was running at WOT, then slowed down entering the no wake zone and the engine just died. I would turn the key, engine would try to start but wouldn't. I had to get towed in. Once I trimmed the engine up to get it out of the water, the carbs drained. Got home and it started right back up. For me, seems like the carbs flooded. My mechanic buddy said it could be the pump diaphragm and/or carbs. Instead of second guessing, I rebuilt the 3 carbs, changed the fuel filter, changed the sparks, replaced the diaphragm(on removal, i noticed that the way it was set up, one of the gaskets was completely out of order that was provided in the replacement manual so i think this was one of my problems), and changed the temp sensor(getting a constant, non-stop alarm, thought the temp sensor would fix it). I could honestly say that the engine sounds as healthy as i've ever heard it and due for a trial run this weekend. I'd be able to provide an update as to if the above fixed my issue or not.

For you, I'd go ahead and rebuild the carbs and ensure the floats are adjusted to spec. The debris may clogged your carbs. Diaphragm swap is inexpensive and if you've never done it, it wouldn't hurt.

Yes I'm thinking not flooding as I sat all night before attempting to restart. So I'm going do pretty much what you did. I'll update when I finish the work or if learn more .

 

[flyingscott]

Have you done a compression test?

 

[Chris1956]

Once the carbs clog, they do not unclog themselves. The carb clog can also cause the motor to run lean and hot, hence the compression test recommendation.

 

[racerone]

With motor running you push in the key.----Enricher valve should open and let extra fuel in ( flooding ) and motor should run rough and slow down.----If there is no change in operation the valve is not working.------

 

[Texasmark]

is that fuel line breaking down? it looks like when a rubber line is giving up

Disconnect a fuel line in the engine and with a clean cotton swab, swab the inside of the line. If you come out with specks, yepper, time for new hoses, new fuel filter and all 4 carbs removed and thoroughly cleaned with solvent, fine wire for any orifices, and 100# compressed air cleanout.

While you are at it replace the line and squeeze bulb between the tank and engine especially if you find tan chips in the fuel filter......when you cut it open and inspect it!

I have 90 and 115 2002 year model engines. After 10 years the 90 running E10 failed the test I described with both internal and external lines. One of the black specks, much larger than yours found its way into the cavity at the bottom of a carb where the high speed jet is located and caused me intermittent WOT problems...going after the solution to that is what put me onto the fix I mentioned. I had thoroughly cleaned the carbs and all but it wasn't until I hit one with the compressed air did I dislodge and find the speck causing my problem.

The 115, running gasoline exclusively, passed the black dot test but failed the tan chip test.....fuel filter almost completely filled with tan chips. Swabbing the inside of the internal fuel line produced no black specks. So on that engine I replaced the fuel filter and the hose between the engine and tank and that took care of that.