Stalling and Starting problems

alldodge

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Merc makes one but they kind of high 91-18078 but it's designed to use the hand held vacuum fuel pump tester
91-18078 fuel fitting.jpg
But could also get some 3/8 gas line, a plastic Tee and some hose clamps.
At max of 10 psi, line and hose claps will work. Most auto parts places will have a straight or elbow fitting to fit the carb.
 

amplay

Seaman
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Sep 29, 2022
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Thanks, but I can't see how to attach the gas line to the pump. Can you be more descriptive? Also, if I jump the Oil pressure switch, will the pump run continuously with the key on but without the engine running? Can I deadhead the pump to test it?
 

alldodge

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Also, if I jump the Oil pressure switch, will the pump run continuously with the key on but without the engine running?
Yes

Can I deadhead the pump to test it?
Yes, but need to get the air out to get accurate reading

Thanks, but I can't see how to attach the gas line to the pump. Can you be more descriptive?
The easiest way is with the fitting above and a Vac fuel pump tester which can normally be borrowed from auto parts store

https://www.harborfreight.com/fuel-pump-and-vacuum-tester-62637.html

Remove the steel line from the carb
Note "I think" you need a 3/8 inverted flare to 3/8 barbed fitting to screw into the carb
https://shop.advanceautoparts.com/p...ctor-3-8-in-x-3-8-in-tube-785-408d/11911134-P

Here is the 3/8 barbed Tee fitting
https://shop.advanceautoparts.com/p...rass-tee-connector-3-8-in-493-0311/22972403-P

Take a piece of 3/8 fuel line and push it over the end of the fuel line, push the nut back away from the end of line. Put hose clamp on hose

Cut fuel line and use the Tee fitting and fuel line and clamps.
Attach another end of the fuel line to the 3/8 barb to inverted flare fitting
Take the last end of Tee fitting with fuel line and attach to gauge
 

todhunter

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Sep 15, 2020
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you may already know this that has compression fittings not flare, need to cut fuel line take a section out and insert this .
Yep, that's the plan. Good pointing it out for others who may not know, though.
 

amplay

Seaman
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Sep 29, 2022
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71
This is a follow up to the issue reported 2 months ago.

I checked the fuel pump, and the pressure was perfect. I then replaced the Needle Value with the newer version (no spring).

This fixes my issue 90%, but the other 10% is very annoying. For instance, last night I went to the boat, it started on first try. We idled for about 30 minutes, and for the next 30 minutes mostly at 4000 RPM. Got back to the marina, where we have an idle zone. Immediately upon reduction of speed, the engine flooded. For the next 200 yards, I had to restart the engine every 15 seconds due to flooding, but was able to limp back to my slip. Any ideas?
 

alldodge

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I would drop the float level just ever so slightly more
 

amplay

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Thanks so much. Are you talking about the float level or float drop. See attached.
 

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  • Pages from MerCruiser 305_cid_50l.pdf
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alldodge

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Float level, my word drop means to have it be lower when it shuts fuel off. Float level is set at 3/8 so make it closer to 7/16. This will keep a bit less fuel in the bowl. If it still floods after this, then it's the needle and seat or pressure
 

Scott06

Admiral
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Apr 20, 2014
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This is a follow up to the issue reported 2 months ago.

I checked the fuel pump, and the pressure was perfect. I then replaced the Needle Value with the newer version (no spring).

This fixes my issue 90%, but the other 10% is very annoying. For instance, last night I went to the boat, it started on first try. We idled for about 30 minutes, and for the next 30 minutes mostly at 4000 RPM. Got back to the marina, where we have an idle zone. Immediately upon reduction of speed, the engine flooded. For the next 200 yards, I had to restart the engine every 15 seconds due to flooding, but was able to limp back to my slip. Any ideas?
If lowering the float doesn’t fix it I believe the spring loaded needle and seat was used to combat flooding issue. That and the non spring loaded needle and
Seat have two different float levels but might be worth trying an oem quality spring loaded needle and seat. Obviously by changing it out u determined what was the issue
 
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