1994 mercury sport jet fuel enrichment system. 90HP

[sledman11]

I have a 1994 jet boat with a 90 hp mercury sport jet engine. I am about 98% certain the the enrichment system is not working. Boat runs great as long as you start it by spraying so gas into the carbs. It starts back up fine If you shut if off and restart it right away. Choke is working fine.

Just trying to learn about how the enrichment circuit works. From looking at the parts diagram I see it has a solenoid. Where is this mounted on the engine? Is the gas that feeds the solenoid come from after the fuel pump or is it gravity fed? I would image the solenoid feeds gas directly into the intake manifold. Does anyone know of a good website where it can buy a electronic copy of the service manual for a reasonable price?

If the rain holds off tomorrow I will try and figure this out but figured there might be someone on here that can give me a head start.

Thanks for taking the time to read this and thank you for any details on how the enrichment system works on the sport jet

Don

 

[racerone]

I see the 94 model with CHOKE flappers.----Doubt that it has an enricher system.

 

[sledman11]

I see the 94 model with CHOKE flappers.----Doubt that it has an enricher system.

It does have choke flappers which are working. If it does not have a enrichment circuit then there is an issue with the gas not being drawn up out of the bowl when engine is just cranking over. It has a primer ball so I have the bowls completely filled to the point where the float/valve closes. Primer ball firms right up once it reaches that point. What would cause the gas from not being drawn up when the engine is not running but just cranking over? Reeds? Engine seems to run great. Yes I know it should not have a primer ball. It was on the boat when I got it.

 

[Faztbullet]

Whats your starting procedure?

 

[sledman11]

It shows an enricher solenoid on the parts diagram for this motor so it appears to have both choke an a enricher. As far as the starting procedure. I have tried at idle with and without the choke on. With throttle applied. It does absolutely nothing until I spray some gas into the carbs. Then it springs to life and runs great. No gas is getting to the intake from the carbs until it starts

 

[racerone]

What is the part # for the enricher solenoid that you see.----Item # on the page as well.----Both systems " not working " seems odd.

 

[sledman11]

What is the part # for the enricher solenoid that you see.----Item # on the page as well.----Both systems " not working " seems odd.

The part number for teh enricher solenoid is 814329T6. It looks like it was an OEM upgrade you could do. It is listed under "instant start kit". So apparently my problem is not with the fuel enricher.since I do not have one. Don't know if it is related but the boat is idling at 2k RPM's which is way above where it should be. That is out of the water.

 

[racerone]

You may find that this " FORCE " outboard engine jet needs to idle higher than a conventional outboard motor.

 

[roscoe]

Starting procedure is important.

Push the neutral / throttle only button and advance the throttle to wide open, then try to start it.

Follow this starting procedure.

Open fuel tank vent

Check the kill switch, place in "run" position

Squeeze fuel primer bulb till firm.

Advance the throttle 3/4 way or more, without putting it in gear. -- This is done by either pushing a button in the center of the controls, or pulling the shift handle toward the driver, or raising the fast idle lever, all depending on what control unit you have.

Turn the key to the on/run position.

Activate the choke by pushing in on the key.
Turn the key to start while continuing to hold the key in.

Release the key and choke when it starts.

3-5 seconds of "choke", is usually enough.

Be ready to pull the throttle back toward the idle/neutral position, when the engine starts and the revs increase.

Continue to pull the throttle back as the engine warms up.

You should not have to use the choke much, if at all, once the engine has warmed up.

Engine should start within 10 seconds of turning the key.

 

[sledman11]

Starting procedure is important.

Push the neutral / throttle only button and advance the throttle to wide open, then try to start it.

Follow this starting procedure.

Open fuel tank vent

Check the kill switch, place in "run" position

Squeeze fuel primer bulb till firm.

Advance the throttle 3/4 way or more, without putting it in gear. -- This is done by either pushing a button in the center of the controls, or pulling the shift handle toward the driver, or raising the fast idle lever, all depending on what control unit you have.

Turn the key to the on/run position.

Activate the choke by pushing in on the key.
Turn the key to start while continuing to hold the key in.

Release the key and choke when it starts.

3-5 seconds of "choke", is usually enough.

Be ready to pull the throttle back toward the idle/neutral position, when the engine starts and the revs increase.

Continue to pull the throttle back as the engine warms up.

You should not have to use the choke much, if at all, once the engine has warmed up.

Engine should start within 10 seconds of turning the key.

Thank you for the starting procedure. I am very familiar with figuring out the best starting procedure having owned over 20 different snowmobiles, 10 different jetskis and a host of other motorize devices. It does not matter what I try the gas is just not getting pulled up out of the bowls. The fuel pump works great and the primer ball is squeeze until hard. The bowls are full to the point they should be. Not sure on these Tilison carbs if the gas should be pulled thru the main jet circuit or if there is another idle/ low speed circuit that should be feeding the gas while cranking the engine. I believe the vacuum at the intake should draw the gas up out of the bowl into the throat of the carbs. A good technical description of the Tilison carb would be helpful.

Only thing I can think of is the floats and not quite where they should be and I am sucking air from the bowls instead of gas when trying to start the engine. I adjusted them so they are parallel (level) to the bowl housing. Just seems odd that the engine appears to run fine if I start the engine by spraying gas into the carbs.

Anyone know of a reliable website for buying an electronic copy of the service manual?

Thanks again for all your help.

Don