Mercury 35 hp outboard timing

[Cmal08]

So I have a mercury 35 hp that ran perfect last year beside low speed idle. I got through the season and then cleaned carbs and put new plugs in. This year its been nothing but issues after messing with the screws trying to get the low idle better. Come to find out after reading a thread on here I messed with the timing adjust screw. I checked timing and it's 0 degrees at TDC but It says set that screw at 3 degrees.. problem is how the heck do I tell when that screw is at 3 degrees. Any help is much appreciated. Thanks!

 

[jimmbo]

Welcome to iboats.
The 3 degrees is not an Idle Timing Spec. It is likely the Spec for the Primary Pickup, which when the Carb is just about to move from from being fully closed. Unlike older cars/truck engines, the timing is what adjusts the Idle Speed, as the Carbs are always fully closed at Idle. There are timing marks/Label on the Flywheel, and a Timing Pointer on the front of the engine. The Calibration of the Timing Marker is usually apart of the Timing Procedures. If you don't have a Factory Manual specific for your motor, Get One.

 

[racerone]

Stop.--------Idle timing is the point where throttle plate opens.------You only set MAXIMUM timing advance.-----Make no adjustment on timing unless you read the procedure and understand it.-------Trouble shooting starts with a compression test.-----Post your numbers.

 

[Cmal08]

Ok so let me explain some more. I never messed with the maximum timing advance. And I never messed with the actual timing. Iv only messed with the screws in the pictures below. Got it running again and everything seems to be back to normal but still will die in neutral. Unless I immediately give it some throttle.

 

[racerone]

The trouble shooting starts with a compression test.------Timing on these motors does not go out of adjustment.

 

[jimmbo]

What's the Serial Number of the Engine?

 

[Cmal08]

Compression is 135 in both cylinder. I'm on the lake now it's running ok but rough starting and almost has to be choked the first 2 seconds and then run back to flip the choke off. Could it be as simple as doing in the air/fuel screw to where it's happy?

 

[racerone]

Yes ----Turn low speed mixture screw in 1/8th turn at a time.

 

[Cmal08]

Iv been tinkering with itittle adjustments at a time but we were heading across Ed the lake at full throttle and it was going great for about a minute or so and then just died completely like it lost all fuel intake. Iv cleaned carbs twice now made sure no clogs in any jets or ports. Also check the fuel line from tank to motor for cracks or leaks to see if it was losing prime and that was good only thi g I have checked is the fuel li es in the engine cowl to the carb but haven't notice any leaks from any of those. I'm just completely out of answers at this point lol. I have mechanic bank ground but never really dealt with marine motors. But you'd think carb work is carb work. Idk any ideas are welcome at this point.

 

[jimmbo]

When the Engine died on the Water, It just quit, or did it slow down and then quit?

 

[racerone]

Test run with another tank and hose.----Or carefully inspect yours from motor to the BOTTOM of the tank.

 

[BWR1953]

Make sure that the gas tank vent is fully open.

Don't ask me how I know.

 

[Cmal08]

It kind of just bogged and died like it lost all fuel supply. Gas tank vent was open haha iv done that before. I'm thinking maybe change hose from tank to motor as precautionary?

 

[Dave1027]

It kind of just bogged and died like it lost all fuel supply. Gas tank vent was open haha iv done that before. I'm thinking maybe change hose from tank to motor as precautionary?

Try pumping the primer bulb when it happens. Does it pick back up? Maybe fuel pump then.

 

[Cmal08]

Still can't figure this darn motor out went out and I got it running decent, then tried going out yesterday about 2 weeks from the last time and it just died after 45 seconds again. Link below is video of it running today.

 

[jimmbo]

Sounds like it is running out of gas. Check every fitting for air leaks, even to the point of smearing grease over connectors/connections. Brake Cleaner will take it off. Being that it runs as long as it does, I suspect there is a leak near, at, or in the fuel tank. Primer Bulbs can be devious little Devils, when it comes to letting air in, but no fuel out

 

[Cmal08]

I thought it was the tank and primer so I switched them out with my other tank for my smaller mercury (8 hp instead of 30) and it's still doing it. So far iv changed tanks, checked fuel pump for torn diaphragm or gunk, cleaned the carb including jet ports and float needle seat, it's 100% fuel related just don't know where to go from what iv done so far.

 

[jimmbo]

Try pumping up the Primer till it is firm, start the engine, then disconnect the fuel line at the motor and pressing in the Check Valve on the connector at the engine, and see how long it runs.

 

[Cmal08]

So update went to go take the carb out again and found that my float bowl vent jet was missing. And come to think of it iv never remembered it being there. Could that be the culprit?

 

[jimmbo]

That is an combination Vent/Air Bleed. If it is missing it will affect Part Throttle Mixture. You can leave it out, just unhook that hose just to the right of your circle, from the fuel bowl cover and plug it with a small ball. Do not unhook the other end of the hose.