'94 Jet Boat 90 (Force, Mercury) Will not start

[orbitzero]

I have a 1994 Jet Storm with a 90HP Force/Merc engine. Bought the boat 2 years ago and have not had much success in getting it to run, better yet start reliably. (Left me on more than one occassion out on the lake!)

Here is where I am now after this seasons effort, great spark (after replacement of bad (in order): battery, spark plugs, Control Module, Voltage Regulator). Checked out the entire electric section (down to the Red stator), built a DVA adapter for my DVM and again all voltages are within spec.

Thought I was good to go as last summer I had a guy rebuild all three carbs, he said it was running fine, before he blew the electric.

Tried to start it up yesterday and could not get it run. Removed the front air intake cover and this is what I see: Gas pouring out of the carb at the bottom of the carb choke/butterfly opening. Checked the 3 carb bowls and though all 3 have small amounts of gas (not enough to be full), clearly the floats have not properly engaged to shut off the gas flow. Again checked all three floats and all appear to be working properly. I think the carbs are OK.

Moved to the fuel pump and have ordered a rebuild kit based on some links that I have read that it could be the culprit, but my question is: if it is not the fuel pump then what would cause the carbs to continue to pour gas into the carb apparently so fast as to not let the float engage and shut off the gas supply.

Thanks in advance for ANY ideas!

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

These carbs have to vent to allow the float to move up and close the needle and seat , Pull the carbs hold each one upside down and blow in the fuel intake , it should pressure lock immediately . the vents are in line with the idle adjustment screw in the middle of the carb body . they may have brass fittings and lines on them . They Must be clear and flow air with no resistance. Clean them to keep the carb bowl from pressurizing and creating a air lock that keeps the float from closing .
The other possibility is the floats are soaked , take each one and put them in some gas for an hour or so if they sink they are bad .

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Thanks KEND for your quick response.

In case you had not guessed it I'm the Electrical one in the group, my buddy is the mechancial one. He had actually pulled all three carbs and did the the pressure lock test, and all three worked perfectly.

We also confirmed the floats are OK, they are not porous, broken and have no gas in them. Interesting note on the floats though, they do appear to be the original ones (or they have been in there for quit a while) as they are quite brown. I have tried to replace them but the only ones that I can find for any Merc Jet are do not look like mine. Everywhere I check they say the floats should be F10346 (891730A01's) but they are very different then the ones in my 3 carbs. Mine have more surface 'defects' than the F10346's. The carbs on the boat were made in Ireland, does that sound original?

The mechanical guy thinks that the fuel pump is providing too much pressure for the carbs to fill and it is causing the engine to flood out, hence the fuel pump rebuild kit on order. One other thing with the fuel pump is that it is missing the gasket that sits near the diaphram, not quite sure why but there was none in my fuel pump. Any ideas?

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

These carbs have to vent to allow the float to move up and close the needle and seat , Pull the carbs hold each one upside down and blow in the fuel intake , it should pressure lock immediately . the vents are in line with the idle adjustment screw in the middle of the carb body . they may have brass fittings and lines on them . They Must be clear and flow air with no resistance. Clean them to keep the carb bowl from pressurizing and creating a air lock that keeps the float from closing . The other possibility is the floats are soaked , take each one and put them in some gas for an hour or so if they sink they are bad .

Do the tests highlighted in red . I really think clogged vents are your problem , nothing else makes sense if the carbs will close the needle when pressure tested upside down .

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Thanks Kend

I will check out the carb again for any residue and double check the floats and let you know what I find. I did get the gasket set for the fuel pump and installed the o-ring and have the putty knife at the ready to re-install the pump in the boat. I'll let you know how I make out. Thanks again for your suggestions.

 

[HD Fatboy?]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

If you have an enrichener on that boat check it, it made my Mercury 115 have the same symptoms. Good Luck!

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Thanks HD Fatboy, I actually have the old school manual key choke, that is not that reliable, but that is for another day.

I took Kend's recommendation of checking the carb floats and seat pins and checking the floats (my floats are different then anyones that I can find on line and I would like to replace them just due to age-anybody have any ideas on how to track down the right ones). Took the carbs out tore them down and checked the components. Removed the bowls, flipped the carbs upside down and blew in the fuel line. The floats stayed engage holding the pin in place, no air escaped no matter how hard I blew into the fuel line. Put the floats in gas and waited. Checked them again and they were still floating, built them back up and reinstalled them. Turned on the boat and same exact symptom, gas pouring out of the carb butterfly opening.

Repeated the process a couple of times always with the same results. Tried them individually on the bench, same symptoms. Really looked like a vapor lock condition where the floats did not engage and gas contininued to pour into the carb.

Took another look at the carbs and saw that the only other path flowing out of the bowl was small pin hole that ran up to the yellowed air hose, pulled the hose and found about 1/4 inch of a reddish/brown goop (think like paint that hasn't fullied dried yet). Used some small drill bits to clean out the hose and a smaller drill bit (no drill of course, just the bit by hand) and the carb also was full of the stuff. Once I got the goop out I used some carb cleaner to finish the job.

Checked the next one, same thing, and the third same thing. Repeated the process on all three, rebuilt the carbs and installed them.

Turned the boat over and it started right up and guess what - NO GAS LEAK!

Still need to do a little bit more work, but this is a good one to add to Kend's carb 101 of floats and seats when you are getting too much gas in your carbs, you might want to check that the air hoses/carb port are not blocked.

I'll let you know how I make out.

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Do not feel bad , the same problem burned me twice , after about 20 hrs or so pull the vent lines off the air intake and be sure you can blow through them into the carb bowls .

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Thanks will do!

New update. I took the boat out on the lake and it started right up and idled great (this is new and improved!), that's the good news. Though the electrical and gas problems seem behind me the boat seems struggling at WOT, actually it does not seem to have any high end beyond about 1/2 trottle. That is the last 1/2 of the trottle doesn't seem to provide any extra speed, though you can hear the engine pick up. So I guess my question is: am I now onto the jet pump, or is there something that else that I should look at first?

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

You need to check carb sinc and throttle adjustment , Remove the air box so you can look down the carbs , Set the throttle at WOT (engine off ) and be sure all the butterflies are level and flat , if they have any angle to them you need to adjust the tie bar and the throttle linkage until all carbs are the same , flat butterflies at wot , be aware that you can open them too much and they will start closing again on the down side of center . Once this is ok back the throttle down to idle position and be sure you barely contact the throttle cam . Also check all idle air adjustment screws they should be 1 1/2 torns out from closed .. then check timing 30 degrees BTDC at wot IN THE WATER tied off to a dock

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Interesting! I thought I was all done with the carbs! I won't get a chance to get to the boat until the weekend, but I can't wait to see in what shape the carb butterfly's are in as I did have the linkage completlely off the carbs while I was working on them and never rechecked the butterfly's. I also do think that the throttle cam is more engaged then you suggested (I think this a legacy to the previously poor running carbs), so that one will be interesting as well to check. Carb screws I know are good at 1 1/2 turns. I don't have a timing light so I'll have to wait until I can scronge one up to check the timing, but I am all over the carbs this weekend! Thanks again for your suggestions. I'll let you know how I make out.

 

[orbitzero]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Well Kend you were spot on with your directions (again!), I confirmed that the butterfly was completely level on the first 2 carbs and when I got to the third it was about 2/3 open at WOT. Spent the better part of an hour adjusting the three of them to insure that all 3 tracked; from competely closed at Neutral- to parallel at WOT. Then I moved on to the Trottle engage mechanizm (just engaged at Neutral) and the carb mix screws (all at 1 1/2 turn out from close). Also took the opportuntity to clean out some sea grass from around the jet drive.

Took the boat to the lake (started right up! I'm beginning to expect that now) and headed for open water. Cleared the no wake zone and opened her up, she planed almost immediately (also added the Natilus Smart Tabs you had recommended to someone) and the boat ran great for the entire time. Not great, but better than anytime I have had the boat out! Ran it for about 20-30 minutes with no issues. Took it back to the trailer and took it home for best cleaning that it has seen in 2 years! Even though summer is moving quickly, I am sure that I will get some fun out of it this year.

Thanks again for time and knowledge, there are plenty of us guys out here that have learned alot from your patience and the time you take in addressing these jetboat questions. Til the next time- thanks again!!!!

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Love to help you guys , I do this cause I got one that no one would help me with and it pised me off , I learned alot about these things and will share with anyone .. LOL this is Bob's revenge on mercury !!! Glad to help

 

[Tony Godsoe]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

I have a 1999 Merc Jet engine which I am Told it is a FORCE engine It will not start I have replaced the Stator and the solenoid and the starter and a new battery Is it true you can fry the stator if you attempt to boost these engines. The boat did work great for one day after I bought it

 

[kend301]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Tony , first start a new thread , second please be more descriptive of your problem .. No spark ? runs Rough ?

 

[beverly10]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

Hell my name is Beverly and i am having the same promblem but i have no spark at all. I have replaced the starter flywhell and coils. i am stuck idk what is wrong with this one it is a 90 hp force inborad jetboat does anyone know what could be happening any help would be great thanls alot to everyone also this boat does not have a swich box.

 

[beverly10]

Re: '94 Jet Boat 90 (Force, Mercury) Will not start

This is bev again. i have a 94 searay radyer 90 ho force motor. i did not tell u what kind of boat it was in the first post