intermittent fuel? problemw/ Merc 150

[rookieflyer]

I just put an '89 150 in the water after it had been sitting for about 8 months. It's a Darrel Brooks (Tampa) motor, but I am the second owner, so I'm not sure of what's original in it and what's not.

The first trial was miserable - it wouldn't get up on plane. I immediately cleaned the carbs and put in new needle seats & a fuel filter (also a new pump top & impeller) I did the carbs because it was smoking and I noticed some fuel overflowing one or two of the bowls. The next time out it gave me three hours of really good running at all speeds, although it was still a bit smoky.

Two days later it started and ran great until after a good hard run for about 10 - 15 minutes I had to settle down in a No-Wake Zone. When I thried to get up and run again, the further I pushed the lever, the slower it went - it felt like it was starving for fuel, but was still smoking. Squeezing the bulb did nothing.

It Idled roughlyand missing badly for about 15 minutes, then it suddenly ran OK again and did so for another hour or so.

As I was pulling into the dock at the end of the day, it did the same trick again, smoke, rough idle, & even stalling. Of course I had just given it a nice WOT blast before the channel to the dock and the latest round of trouble.

Instinct is telling me that there's too much fuel at these times, and I'm pretty sure the small tubing that runs from each cylinder to the small fittings beneath the carbs is all mixed and out of place. I also wonder if the choke may be getting stuck at times.....but I'm pretty new at this, so I thought I'd ask for some experienced views.

Any ideas for me?

[vector mike]

Havn't I heard this before? I almost gave a answer untill I realized we allready talked about this on the other thread. :rolleyes:

[rookieflyer]

I got nervous when I realized that hours went by and a dozen or so people checked the original message, but then none replied.
With the weekend getting closer by the minute, Ijust had to do something! I assumed that my first posting was just too wordy for most people to bother with, so I posted "simpler post"
Sorry for the inconvenience....

But really, does that whole three-day history sound like it could be caused by these hoses being mixed up?

[vector mike]

It sounded to me like it was flooding out. But you said you changed your needle and seats. What kind of fuel pump are you using? Do you have a filter before the carbs? I thought maybe you were getting dirt in the needle and seats or over pressureizing the needles. Hope you find your problem.

[rookieflyer]

It is the 'old style' factory fuel pump.

I put a new inline filter before the pump......could it have been pushing debris into the bowls from within the pump? Isn't there a screen inside the pump that might show me if this could be the case?

Pump to top carb is still as original, except I did replace the fuel lines.....

Could it be the enrichner or something like that causing excess fuel to flow?

[Talon2.5]

the enrichener pulls fuel from the top carbs bowl, and yes it could be as simple as that, it's worth inspecting if you have fuel dripping from the center and bottom carbs

[Talon2.5]

if it has dual fuel pumps you may have one of the pumps not feeding after a hot run, which may be a worn diaphram in one or the other pumps also

if ya re-did the carbs it may be worth inspecting and replacing the pump diaphrams, they stretch with time and just flutter so to speak instead of pumping, those pumps are run by crankcase pulse and wear out and/or get stiff with age

[vector mike]

What happened? How come you didn't suggest to ditch the stock pump and go electric?:confused:

[rookieflyer]

I found the needle valves were getting gummed up with blue-gray slop, and assumed it was water in the fuel. I put a new water separating filter in and it started running much better.

Still too much smoke, though......on land, anyway.

In the water, I thought that maybe it would clear out, but I didn't get very far this AM - it blew a spark plug out of a soft hole.
(see post on stripped plug hole)

Anyway, the bleed lines and a new fuel filter made a big difference. I clamped the enrichener line to block it, and it didn't seem to make a difference - still too much smoke IMHO.

After dealing with the bad plug hole, I think I'll check all the jet sizes.

Does anyone know what they should be, especially idlers?

TIA,
Chris

[vector mike]

I have the whole list for all the jets in all the WH carbs at home. I can tell you what they should be when I get home if someone doesn't before then. :)

[rookieflyer]

Got 'em. thanks.

[FASTPACE]

ROOKIEFLYER: WHAT WERE THOSE JET SIZES? I HAVE A 88 MAGII
AND WOULD LIKE TO COMPARE TO SEE IF MINE ARE CORRECT. I TOO AM SEEING ALITTLE SMOKE ON THE FLUSHER. I AM WONDERING WHY I CAN TURN MY 23P ONLY 5400 ON MY 17'6" HYDRA SPORTS AT 58 MPH?

[vector mike]

I can tell you what jets came stock in them.

[rookieflyer]

Sorry, but I haven't been able to get out to the boat to read the carb numbers yet. Bear with me while I catch up with life here.....

[vector mike]

When you find out what the numbers are just e-mail me and I will look it up for you.:)

[Talon2.5]

mike,

you, me and vectorpat need to shoot the **** a bit at the east lake gathering :D