Carb issues

[jeremiah89]

I have a 1991 Renken Seamaster 2688 with a 5.7 OMC snd a Holley Carb. The issue i am having is at high speeds for awhile it'll fall on its face no power barely moving barley idling popping and though the carb and eventually the engine stalls. There is usually smoking coming out of the carb when this happens, if you let it sit for 5 or 10 minutes it's fine for a little while. I also have to hold the throttle wide open to get it to fire and it takes about 5 to 10 seconds. Once you get it running you have to hurry up and drop it back to neutral and throw it in gear it'll stall. Trying to park in a slip is nearly impossible because from Drive to Reverse it'll stall alot. Sounds like a carb issue to me not sure though. Thanks for the help

 

[Lou C]

You may have sticking floats or a blown power valve, there are like a gazillion vids on how to rebuild Holley carbs out there, it's basically a 3 piece unit with the center throttle body, and the 2 float bowls some have a metering block on the front bowl only (4160 style) and a metering plate on the back bowl, some have metering blocks on both (4150 style). There are build numbers on the air horn that you can use to look up which Holley kit you will need, the main thing with carb rebuilds is always the cleaning, soak in chemical cleaner (careful!!) and blow out all the passages, air bleeds and jets. Replace all gaskets, the float seats and needle valves, measure float drop, and install a new power valve of the correct rating. The air horn is where the choke flap is attached you will find the build #s there. Go on to www.holley.com
for more info...
here's a 4160

 

[Scott Danforth]

if you still have points, could also be an ignition issue in addition to the carb issue. Lou has you in the right direction with the carb.

 

[jeremiah89]

It has electronic points now.

 

[racerone]

The " popping " sounds coming out of carburetor may indicate an intake valve or timing issue.

 

[jeremiah89]

Would it be intermittent?

 

[Lou C]

Could be sticking intake valves, it happens and the cause could have been the water intrusion

 

[racerone]

I re-read post #1 and I think you need a new carburetor.

 

[jeremiah89]

Could be sticking intake valves, it happens and the cause could have been the water intrusion

Would it be intermittent it only done it twice in 2 hrs? We went20 something miles

 

[Lou C]

hard to say really there can be multiple causes for backfires/misfires. Compression test, will find sticky valves
other causes:
fouled spark plugs
plug wires with too much resistance
corroded contacts inside distributor cap, cracked cap or rotor
carb issues.
It's all auto shop 101.
BTW the backfire or misfire can also cause water to be sucked up the exhaust.

 

[jeremiah89]

Could be sticking intake valves, it happens and the cause could have been the water intrusion

Would it be intermittent it only done it twice in 2 hrs? We went 20 something miles

 

[jeremiah89]

hard to say really there can be multiple causes for backfires/misfires. Compression test, will find sticky valves
other causes:
fouled spark plugs
plug wires with too much resistance
corroded contacts inside distributor cap, cracked cap or rotor
carb issues.
It's all auto shop 101.
BTW the backfire or misfire can also cause water to be sucked up the

hard to say really there can be multiple causes for backfires/misfires. Compression test, will find sticky valves
other causes:
fouled spark plugs
plug wires with too much resistance
corroded contacts inside distributor cap, cracked cap or rotor
carb issues.
It's all auto shop 101.
BTW the backfire or misfire can also cause water to be sucked up the exhaust.

Thanks man I'll start with the carb then compression test everything else you named is either new or I've checked.

 

[Lou C]

Only time I had a back fire through the carb was after a bad overheat back in '13, the first start up in '14, warning signs were that, and a bit of sodium (salt water boat) showing up in an oil analysis I did the following year. That was the beginning of the head gaskets starting to leak, although the engine still ran fine pretty much all the time. Still it ran fine through '14, '15, and at the end of '16 the head gaskets finally blew. So after that I did a top end overhaul with reman heads, new gaskets/head bolts new exhaust etc.

 

[Star64]

Power valve one pop back through carb on a holley and might as well replace it it will help with acceleration also