Mariner with exesive fuel problem/wet cylinders

[sschefer]

Hi Folks,

This is a 100hp, 1991 Belgium made, 4 cyl Mariner, carbed with oil injection. Ignition did have a problem but the stator, trigger, rectifier and switch box are new. The spark is good and timing seems best when set a 4 degrees BTDC, (the manuals all say 2 ATDC to 4 BTDC). Compresson is 125 on all cylinders.

The carbs are WME's and have been rebuilt after a 24 hour soak in Gunk and all passages were blown out with compressed air. The floats are set at 7/16" and the bulb gets hard with squeezed. The original in-line fuel filter has been removed and I'm using a Racor fuel/water separator with a new filter. Fuel flow from tank feels good. Tank is a 20 gal and 17 gals were added to the remaining treated gas from last Oct. The fuel has 1 can of SeaFoam in it. The engine has also been decarbed. The accelerator pump is set to .030 at WOT. Idle screws on #1 and #2 carbs will lean out and stall the engine when adjusting for the lean side. When going to the rich side the engine smooths a little but runs rough and never gets worse no matter how rich.

Smoke is not that bad under any condition except on startup when it blows a pretty good cloud. When the plugs are removed after running in a tank the plugs are wet and the fuel seems to show adequate oil for lubrication.

In the tank and in gear, it has rough accelleration. I only took it to 2000 rpm and just to see if 3 and 4 were firing. It was hard to tell and it misses badly all the way up as if it were leaning out. I suspected fuel pump but when I pulled the plugs they were wet and not that nice brown color that they should be. It runs better on a gapped plug than the perma gaps. The manual says either plug is fine.

Any ideas or past experiences that you could share would be extremely appreciated. I've searched the threads and haven't run accross anything that sounds like my problem.
.

 

[sschefer]

Re: Mariner with exesive fuel problem/wet cylinders

Well, I guess you all are as stumped as I am with this one. I'm going to tear it back down and order a fuel pump kit, check valves, injectors and needles for the carbs. What the heck else is left. If this was a 4 stroke I'd be looking for a vacumm leak. Anyone thinking reed block here? A primary compression check holds steady at 5lbs for 15 minutes so the seals are good and that should mean that the reed blocks are o.k. too? (yes/no).

 

[sschefer]

Re: Mariner with exesive fuel problem/wet cylinders

Still stumped? You have every right to be. You couldn't have known that the P/O must have had somebody PO'd at him because somebody dumped dirt in the oil tank. The mistake was mine, I took the inline fuel filter out when I put the Racor fuel filter/water separator in. Dummy me didn't think about the oil comming in after the filter.

So I've got it all torn apart again for cleaning. I know the carbs are full of junk and the float needles are probably stuck wide open. That's why I can lean it out but enrichening it doesn't make a difference.

I took apart the accellerator pump and it was full of dirt so I bet the fuel pump is the same way.

So, let this be a lesson. Never remove the inline filters at the engine if you still have your oil injection system intact.

What happened here was that I changed all the ignition system out and fixed that problem but at the same time, I created a new one by removing the filter. Both problems have similar symptoms but neither are related. I have not doubt the stator was bad as well as the switch box because on the bench they test bad.

 

[sschefer]

Re: Mariner with exesive fuel problem/wet cylinders

Just a quick update - There was dirt in the oil, I ran it through a paint strainer. There was some but not as much as I thought. I took apart the inline filter from the accelerator pump to the injectors and found a rubbery substance. I then took the fuel line that was on it originally down to Kragens and they matched it to windshield washer hose. The guy said he can tell because fuel line has a red stripe and this has a blue.

My suspicions are that the tubing broke down from the fuel and that's what clogged the injectors. Later I noticed that my hands were black when I handled the old hose. The dirt in the oil just complicated matters. No. 4 carb was clean, I haven't got the rest of them torn down yet.

 

[sschefer]

Re: Mariner with exesive fuel problem/wet cylinders

Case closed: Problem was Ethanol.

 

[mnall65]

Re: Mariner with exesive fuel problem/wet cylinders

Hmmm I seem to have a similar problem with my 1985 magnum 150 although I haven't tried rebuilding the carbs, motor runs good it seems like. But when I drop her in gear and mash the pedal it limits itself to 2000 rpm or there abouts. It idles a bit rough and smokes quite a bit at times though. Every now and then I can get it to open wide up and run right but then it will drop back down to around 2000 rpm

This boat set for 3 years and I bought it, turned the key when I got home after checking some things and it fired right up, had to replace a coil, reattatch plug wires and such. I have put 91 octane in it and Lucas injector cleaner in it and sprayed a can of carb cleaner in there. Think I should change the plugs also?

Nice job fixing your problem, i'm sorry you had to do it all yourself.

If anyone has any ideas for me let me know lol.

 

[j_martin]

Re: Mariner with exesive fuel problem/wet cylinders

I bought a boat with a doggy 150HP XR4 on it. After cleaning up all the mess, cleaning out the sludge from the fuel tank, and tuning it up right, I have run nothing but non-oxygenated (no alcohol) fuel in it. Not a lick of trouble.