95 Sportjet 120 hesitation

[dcmcmullen]

Bought a 95 SeaRaider F14 with a 120 sportjet the end of last summer. Engine sn#0E100830. The guy I bought if from had only used it about 5 times in over 3 years. He bought it used from a friend of his that never used it. Engine starts up and idles, stalling occationally. Idle seems a little slow and if I let it idle too long the overheat alarm sounds (engine book say's too low idle will cause overheat on the sportjet). The main problem is when excelerating pulling a skiier, sometimes it goes fine but most times its flat(no go just high idle). When this happens there is a strong smell of raw gas and heavy smoke out the back. I took it to a mechanic (tough to find a shop that will work on the sport jet) and they did a tuneup and a service. Spoke directly with the mechanic on the hesitation problem and he said the tuneup should take care of it. He tested it and it runs fine. Before spending a weekend at the lake I tested it in a local canal. It seemed to run fine however I did not test it under load. Got to the lake and sure enough the hesitation was still there. Took it to a mechanic near the lake and he said the 2 top plugs were fouled and replaced all 4 of them, he tested it and said it's fine. Put it back in the lake and the hesitation returned within a 1/4 tank of gas. Now I am trying to troubleshoot it myself. I pulled the plug wires off the bottom 2 cylenders and started the motor. It idles like it usally does. Connected the 2 lower plugs, idles the same. Disconnected the top 2 plugs and the motor won't start. Connected the top 2 plugs started the engine and while idling I pinchedthe fuel line off until the engine started to stall and released it. Hit the gas and it took off fine, backed it down and hit it again and it hesitates again. Pinched the fuel line again, released it, takes off fine. Do I have a problem with the lower carb?? Sorry for the long winded post.<br /> Thanks,<br /> Doug

 

[clanton]

Re: 95 Sportjet 120 hesitation

I would do a compression check, spark test, remove carbuators and clean, clean/check fuel filter, replace fuel pump kit, check thermostat, and a link/sync. When you do the carbuators you need manual that matches your engine serial number, because the carbuator main jets are not the same size. The manual I have is for a 120XR2 sport jet dated August 1998 calls far jet .088 top carb, .090 lower carb.

 

[wakataka]

Re: 95 Sportjet 120 hesitation

dc - <br />Sure sounds like you might have the wrong jets in it and it's flooding out. Did you buy it from someone who lived at a higher altitude? The manual lists about 4 or 5 different jet sizes depending on the altitude you run at.<br /><br />One other caution, you can fry the ignition system if you run the engine with the plug wires ungrounded. If you're going to pull them, put an old plug in the boot and ground it while you're testing the engine.<br /><br />Finally, buy a manual. These engines aren't particularly hard to work on, but you need to have the book. The Clymer one is OK but the factory one is better.

 

[Capt Ken]

Re: 95 Sportjet 120 hesitation

Sounds to me like you may have a stator getting weak and dropping the ignition voltage. Weak voltage to the coils will result in the same symtoms.

 

[dcmcmullen]

Re: 95 Sportjet 120 hesitation

Thanks for the replies. <br />The boat has always been in So Fla. The compression is approx 120 in all cylinders (I used a press in tester rather than a screw in as it was less expensive). The first mechanic that worked on it said the compression was fine and the electrical system is ok however I did have to have the rev limiter replaced. He also replaced the fuel filter with the factory recomended as it had a glass see through one on it. <br /><br />I have ordered carb kits and manualand will start there, hopefully they will be here by within 2 weeks. <br /><br /> Thanks again

 

[ODDD1]

Re: 95 Sportjet 120 hesitation

DC, you haven't noticed any water on those lower two plugs, have you? have seen many exhaust manifold gaskets leak on these units, generally the lower 2 cylinders are the ones that get wet..

 

[spoma]

Re: 95 Sportjet 120 hesitation

I know it has been a while since this thread was touched but I seem to be having a similar problem with my 95 sportjet 120.

The problem I am seeing is that it will start up fine and fun for 5-10 minutes ok. Then it will just lower the RPM and eventually stall. Once it stalls it takes 15 minutes or so to get it to start up again. Then it goes through the whole process again. But if I run it at medium RPM (2000 or so) it appears to run all day.

I took it to a mechanic and he said there was water in the fuel and wanted to rebuild the carbs but couldn't get the kits anymore.

I was going to try taking the carbs apart and cleaning them. I also think I found the kits online but can't be sure they are the correct ones. Does anyone know if FK10103-2 is the correct parts for these carbs?

I have good compression and I am getting good spark on all 4 plugs. I might try and get a water separation filter that I have read a little about online. Are these tough to install?

Any help would be appreciated.

 

[tashasdaddy]

Re: 95 Sportjet 120 hesitation

it sound to me that you need a complete tune up, impeller, carb cleaning, linc n sinc. the motor sat up and was not maintained.

 

[JB]

Re: 95 Sportjet 120 hesitation

This forum is for Non-Repair topics, spoma, and this thread belongs to the original poster, who posted when it was a general forum..

Please do not hijack it.

Go to the appropriate forum for troubles and start a thread about your trouble.

Thanks for your cooperation.