96 HobieJet 95XR only starts with "manual choke"

[wahlspyder]

Mercury 95XR. Seems to be pumping fuel fine. If I cover the carbs with my hand, it will start, then i can take my hands away and it runs. Every time it is shut off it needs the "hand" choke. Carb issue? Reed valves? It has the auto enrichener, but no electric choke. The resistance of the auto enrich valve is 26 with my cheap meter (manual specifies 18-20 ohms cold and near infinity hot)

 

[Bruce]

I was going to suggest that it is a carb issue but you already figured that out. Hopefully your knowledge of rebuilding carbs is greater than mine.

 

[wahlspyder]

Guess I'll pull them apart and see what I can find. I imagine I'll find something plugged.

 

[Bruce]

@Cobra Jet Steering LLC, @Speedling, do you have any thoughts?

 

[Cobra Jet Steering LLC]

Not familiar with that motor but if it has no choke and it uses some sort of fuel primer, I would look for why it won't work obviously that is the first culprit

 

[Cobra Jet Steering LLC]

also a lot of older 2 stroke skies used a manual primer so perhaps he can find one and convert to a manual fuel primer to start the engine if he can't fix the original one

 

[Speedling]

Mercury 95XR. Seems to be pumping fuel fine. If I cover the carbs with my hand, it will start, then i can take my hands away and it runs. Every time it is shut off it needs the "hand" choke. Carb issue? Reed valves? It has the auto enrichener, but no electric choke. The resistance of the auto enrich valve is 26 with my cheap meter (manual specifies 18-20 ohms cold and near infinity hot)

If i can bug my buddy tomorrow I will explain this hand choke thing to him and he may have an answer. He's a great knowledgable guy that has fixed every motor I could have imagined. I haven't heard of an auto enrichener but I am going to guess it's a vacuum based system to feed more fuel as needed. How does the choke work on the motor?

 

[Speedling]

just trying to find information!
http://www.boats.net/parts/search/Merc2/Jet/95XR (JET DRIVE) 1996/0E145580 THRU 0E151579/CARBURETOR (SERIAL # 0E203000 THRU 0E315904)/parts.html
A good service bulletin that touches on choking it slightly:
http://marinemechanic.com/merc/sportjet-90-update-en_09.pdf
http://www.boatinfo.no/lib/mercury/manuals/90-120_sportjet.html#/0

 

[wahlspyder]

Not sure how the auto-enricher works. It has a slide that looks like the slide on a motorcycle carb. There is a paraffin pill inside that melts to allow it to move. The specs say that the resistance through the valve should be 18-20 ohms when cold and near infinity when the engine is hot. I got somewhere around 26 ohms on a 90 degree day. The auto enricher is mounted to the reed valve assembly it looks like according to the manual. That was why i asked if maybe it was a problem there. It also has a primer bulb inline between the tank and the fuel pump. I can see through the inline filter between the pump and the carb that it is getting fuel to the carbs.

 

[Jgorm]

I'd guess the jets are clogged, or the float is low. Too little fuel cause it to lean misfire until you manually choke it to richen it up.

 

[wahlspyder]

Once it starts,it seems to run well. It just isn't rich enough to start

 

[wahlspyder]

Took carbs off, cleaned them, blew air through everything. Got some crud out. Put everything back together and it seems to be good. Fingers crossed

 

[wahlspyder]

Took it out for the first time. Very pleased. Thanks to all who contributed!

 

[RedBarron55]

Make sure you have the throttle rigged properly.
For t he enriching system to work the butterflies must be completely closed per the manual.
If they are cracked open then the enrichment valve will not work.
The control must be in the center idle position.

 

[JRicketts1964]

Mercury 95XR. Seems to be pumping fuel fine. If I cover the carbs with my hand, it will start, then i can take my hands away and it runs. Every time it is shut off it needs the "hand" choke. Carb issue? Reed valves? It has the auto enrichener, but no electric choke. The resistance of the auto enrich valve is 26 with my cheap meter (manual specifies 18-20 ohms cold and near infinity hot)

I have the same engine in my Hobbie jet. I'm getting water into the bottom two cylinders.

 

[RedBarron55]

Do a search here for my posts n water in cylinders.
I found that on my motor the problem was the base gasket letting water leak from the exhaust water jacket where the cooling water from the jet pump comes in through the no longer used 3/4" hole in the front bottom of the water jacket under the base and into the exhaust area.
In my case the block had been replaced with the gasket for an outboard that was probably sent with the overhaul kit and it does not seal the passage.
I filled that hole with JB Weld and later replaced the incorrect gasket with the proper one.
It took a heck of a lot of looking to find the problem.
My suspicion is that occurs a lot when the engines are worked on over the years.
Of course it is also possible that there is a gasket leak on the exhaust manifold cover or head gasket, but that was not the case on my engine(s).
Many probably have that issue as they say that the engine will fill the bottom cylinders on the service adapter and hose if the water is started before the engine. My engine used to do that, but not after I fixed the real problem.