Sport Jet 90 Starting Problems

[taxane_chemist]

Okay, I have read enough to know there are alot of issues with the Sport jet 90 and here are mine. First, is it okay to start the engine with the boat out of the water? The previous owner would start it while running water through the engine flush kit (located to the right of the engine facing foward) connected to a garden hose, however some of what I have read indicates that I should not do that. Second, when I do start the engine out of the water (with the garden hose attached) I pull the throttle only button out and turn the engine over using the choke. The engine will start on the first or second try, run for 30-60 seconds and then stall. Once it stalls I cannot start it again. The next day I can repeat the whole deal again (starts easily, runs for a minute or so, stalls, won't restart). Are these 2 questions possibly related? Can I expect the engine to stall this way if the boat is in the water? I'm new at this so any advice is welcome. My boat is a 1994 Regal Rush.

 

[mitko]

Re: Sport Jet 90 Starting Problems

Hi, I have the same problem in or out the water, the garden host is OK, if you learn somethig let me know. Thanks

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

You are not supposed to run the engine with the flush kit. The flush kit attaches to the engine through a small hole in the top of the engine.<br /><br />I really suggest you get a manual, it clears up a lot of questions.<br /><br />In order to run the engine, disconnect the one inch diameter hose from the jet, and buy adapters to fit your water hose onto this hose.<br /><br />As far as your starting problem, you need to determine if you are getting spark when it wont start. If no spark, check out my homepage (icon above) to diagnose.<br /><br />If you do have spark, you need to check it is getting fuel. Perhaps your fuel pump needs rebuilding?<br /><br />Ken

 

[taxane_chemist]

Re: Sport Jet 90 Starting Problems

Thanks Ken,<br /><br />I have a service manual on order now. I have checked out your page and ran the diagnostics up until the switchbox tests (keyswitch, stator (red), rev limiter, trigger, coils). So far everything is okay. The plugs seemed to be sparking when I first checked but they looked kinda weak so I replaced them with Champion L76 as per the owners manual. Cylinders 1 and 2 diffentantly sparked with the new plugs but when I retested the old plugs (this time at night) I saw nothing. Just when I was about to test cylinder 3, the battery gave out on me. If I do get spark on all 3 cylinders with the new plugs and she still won't start does that point to a fuel system problem instead of an ignition problem.<br /><br />Thanks again for all your posts.<br /><br />James

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

Judging from your symptoms, I would say if you have spark, you need to check the fuel supply.<br /><br />If you dont know when the last time the carbs were rebuilt, I suggest you do it and also rebuild the fuel pump. The fuel pump rebuild is super simple, and the carbs are really easy to rebuild also. <br /><br />Do you have a new fuel filter? Is the gas in the tank good? Does the tank have trash in it?<br /><br />Ken

 

[taxane_chemist]

Re: Sport Jet 90 Starting Problems

Ken,<br /><br />Since my last posting I have recharged the battery and verified that I do get spark with the new #3 plug. I am still waiting on the manuel so I haven't done alot more. I did pull the fuel line from the base of the carburetors and cranked the engine for a few seconds. It appeared to me to have good fuel flow. I bought this boat last Oct. and the guy cranked it and let it run for a few minutes. He then switched it off and restarted it with no problems. I let it sit for 2-3 weeks before I tried to crank it myself. It would only run for about 30 seconds and then die. I could not restart. At that time the fuel tank was almost empty so I filled it with fuel and stabilized. I followed the other winterizing procedures according to the owners manual however without really being able to run the boat to circulate the treated fuel. Fast foward to 2 weeks ago, I put the battery back in and it started easily but died after about 60 seconds. I have not been able to start since. If the fuel flow is okay as it seems to be, then I am beginning to think I should rebuild the carbs. I do observe some very minor leaking from the carbs. I guess it could possible be bad fuel but it appeared to be acting this way before I winterized it. Any other thoughts?<br /><br />Thanks again for all your posts. You are truely the guru of sportjets.<br /><br />James

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

James, the problems with Sport Jets is that even when they are running perfectly, they can sometimes be a bear to start. I know this will get a lot of frowns from everybody, but sometimes you have to give it a shot of starting fluid to get it going again. It beats rowing. <br /><br /><br />On your starting procedure:<br /><br />Do you move the throttle foward a little when starting? I usually move it some, just to give it a fast idle.<br /><br />When it is running and wants to die, have you tried to hit the choke again, to see if it picks back up again. When my carbs needed rebuilding, I could keep it alive by pushing in the choke momentarily.<br /><br />It really sounds like carbs, so I would start there.<br /><br />Ken

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

Check timing with all spark plugs removed, and spark plug wires grounded. Timing should be 32 degrees BTDC at WOT.<br /><br />Ken

 

[taxane_chemist]

Re: Sport Jet 90 Starting Problems

Ken,<br /><br />When I try to start I pull the throttle only button out and advance the throttle slightly.<br /><br />Also, I finally got the manual and saw that the fuel should not be pumping in pulses which is what mine appeared to be doing so I took the fuel pump apart and sure enough there were minor cuts in the diaphragm around the screw holes. My question is I could not find a rebuild kit on mercuirserparts.com only individual parts. Should I replace the diaphragm and all gaskets or what? I also took the carbs off. I was going to order a rebuild kit but the guy at the parts store suggested I give it a good cleaning first assuming I don't rip any of the gaskets. Once I get these parts back on the engine I will check the timing.<br /><br />James

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

Hmmm, I cant remember on the fuel pump rebuild kit, but I thought I ordered one. Maybe the parts counter guy just ordered all the parts, cant remember.<br /><br />As for the carb rebuild kits, there are very few pieces, just mainly the gaskets. There is very little to actually rebuild. Take the bowl cover off, and the float, and let them soak for a long time in a solvent. If you get them apart and can reuse the gaskets, there is no need for the rebuild kit.<br /><br />Ken

 

[taxane_chemist]

Re: Sport Jet 90 Starting Problems

Ken, <br /><br />So I was taking the carbs apart and unfortunately broke one of the idle tubes. Went to the parts store and the schematic shows no idle tube for 90 sportjets with non-oil injection. I went and got my clymers manual to show the shop guy what I needed. Unfortunately the manual also shows no idle tube for the early 90 HP models but does show one on the later 90's and 120's. My boat has the earlier type carbs but had idle tubes. Do you know if this is a mistake in the manual and in the parts list schematic or is this carb not suppose to have idle tubes. Maybe someone put them in in the past? Check out the manual and you will see what I mean. The guy at the parts store just shugs his shoulders. Any insight would be great.<br /><br />James

 

[kenimpzoom]

Re: Sport Jet 90 Starting Problems

have you tried looking on<br /><br /> http://www.mercurypartsexpress.com <br /><br />I look in my manual when I get home.<br /><br />Ken

 

[taxane_chemist]

Re: Sport Jet 90 Starting Problems

Ken,<br /><br />I hate to keep asking these questions but I keep running into them. According to the Clymer manual the carb jets below 2500 feet elevation should be 72 for the top and middle and 74 for the bottom. Mine has 70, 70, and 72, which is listed for 2500-5000 ft. according to the manual. I would run at 500 ft or less. Somewhere in this forum however someone mentioned that a service bulletin was issued recommending a jet change. Do you think I should go up to 72, 72, 74? Does it make that big of a difference? <br /><br />James

 

[Capt Ken]

Re: Sport Jet 90 Starting Problems

I think you should leave the jets alone. Your engine is flooding out. Its due to one of two problems. Either the carbs are running too rich and flooding the cylinders out, which is the reason you are unable to restart. Or your stator is getting weak causing a weak spark. This will cause the same outcome. There just ain't enough spark to keep burning the fuel and finally floods out. If it was a fuel delivery problem, you would be able to restart by choking it but by allowing it to sit overnite, the flooding condition is cleared up and you can restart. I believe your problem is the second one. Stator warms up and the voltaged, which is marginal to begin with, is dropping and the fuel is flooding the spark out.

 

[tuckersboat]

Re: Sport Jet 90 Starting Problems

Originally posted by KenImpZoom:<br /> You are not supposed to run the engine with the flush kit. The flush kit attaches to the engine through a small hole in the top of the engine.<br /><br />I really suggest you get a manual, it clears up a lot of questions.<br /><br />In order to run the engine, disconnect the one inch diameter hose from the jet, and buy adapters to fit your water hose onto this hose.<br /><br />As far as your starting problem, you need to determine if you are getting spark when it wont start. If no spark, check out my homepage (icon above) to diagnose.<br /><br />If you do have spark, you need to check it is getting fuel. Perhaps your fuel pump needs rebuilding?<br /><br />Ken

 

[tuckersboat]

Re: Sport Jet 90 Starting Problems

Just bought a 95' bayliner Jet (I think) with a sportjet 90 and I'm having problems keeping it running. This is my first boat so I know nothing. Changed plugs, fuel filter, and an after market fuel pump from advanced auto, that was probibly the wrong thing to do. The problem is, starts fine at home but as soon as it goes in the water it wont start for crap. but when I get it back on land it starts. What the HELL could it be? It did this before part changes.

 

[wapayne]

Re: Sport Jet 90 Starting Problems

I have a starting problem. My needle jets are sticking and won't allow fuel in. I can blow in the small line on the sides and it forces the floats down. It will run but misses a lot. After a while it will not start. Back to the air through the tube. I replace the needle jets,clean out the carb but the problem is still there. Any ideas? Bill

 

[CharlieB]

Re: Sport Jet 90 Starting Problems

Sorry Bill, this is a very old thread.

Start a new thread, spell out your boat/motor/and problem and we will help guide you to a resolution.