Fuel pump for Mariner 75 , two stroke, solenoid valve

Does anybody know what is the solenoid valve in fuel supply for?

The solenoid valve ( enricher ) opens up when key is pushed in.-------------It allows fuel to bypass the carburetors for cold starting.-----Motor must be cranking for it to work properly.---------------Motors equipped with it do not have " choke flappers " installed.

Yep - it's for the electric choke (enrichment system).

When you hold in the key (choke position) it sends power to the solenoid (enrichment valave) which "opens" and pumps some fuel into the intake manifold to assist with a cold start. In a multi-carb setup the fuel comes from the number 1 carb bowl (top) and is fed into the manifold via a small tube to a little fitting at about the half way point on the manifold itself.

Without this system you would have to crank the engine until the fuel pump started "pumping" and enough gas got sucked through the carbs to get the motor to start which would be very hard on the battery.

Thanks racerone. Does it mean that solenoid inject some quantity of fuel into intake manifold to all three carbs? I have problem with cold start. It is necessary to crank the engine for the while....

Thanks galamb,

I understood that solenoid adds some extra fuel into top carb only. Mid and bottom carbs are not enriched with extra fuel? As I have problem with cold start and it is necessary to crank the engine quite long can it be a problem with solenoid or somewhere else...?

I understood that solenoid adds some extra fuel into top carb only. Mid and bottom carbs are not enriched with extra fuel?

Click to expand...

My Merc. manual says all 3 carbs get pressurised fuel from the enrichener valve when the key is turned on and pushed inward. I like to hold my key in for a 10 count when cold starting so that the cylinders get a rich dose of fuel when cranking...it fires right now. When I crank it right away while holding the key in it won't start worth a s..t.

No, in a 3 carb setup the fuel is injected directly into the intake at a point in line with the middle carb. The enricher "scavenges" it's fuel from the bowl of the top carb.

It then (squirts) it right into the intake, bypassing the carbs all together - so each cylinder should get it's "fair share".

Here's a diagram...

Mercury Service Manual 90-830234R04 May 2003
Enrichner Systems
Description for 3 Cylinder Engines
1995 and Earlier - "Fuel flows (gravity fed) from the top carburetor float bowl to the fuel enrichment valve."
1996/1997/1998 - "Fuel is supplied to the engine through fittings located in the top, middle and bottom carburetors."

Thanks galamb

Thanks guyjg