Newbie: 1998 Sportster Twin 717 (85hp) -- Trouble W/ Starboard, Plz Help!

[CanuckJetter]

Howdy everyone! First time poster, and first time boater over here. I'm really hoping that one of you guru's may be able to please point me in the right direction.

I just purchased my first boat, a 1998 Sportster 1800 (18ft - Twin 717 engines) and I'm already running into the newbie basic issues!

The port engine seems to be running very well (though I sucked a rock into the impeller right out of the gate...apparently these vacuum pretty hard).

The starboard engine has some very bizarre issues:

On land, the engine can be hard to start or will not start at all. In water, same thing. I do not appear to have any throttle control unless WOT (then it gains a tiny amount of juice). Checking actuation of the throttle shows that the throat opens and closes correctly. Just to be safe, I've removed the throttle cable and choke cable from the carburetor and tried manual actuation to no avail. When I -can- get the engine running, it seems to sputter/idle at 1500-1800 RPMs (in water) ... with the throttle doing literally nothing at all. I just compression tested yesterday and pulled about 135 on both on this engine (accidentally left the throttle closed for this, don't know if that hurts/helps numbers. 4 cranks on charged battery). I've pulled the spark plugs, and they appear to be quite clean and damp from fuel. I've checked (with the airbox off at idle on the water) and I'm getting a healthy spray from the carb (enough to splatter the eyeballs a little if you stick your head in too close). For kicks, I found the idle adjustment screw closest to the fuel tank and attempted micro-adjustments (1/4 turns) and then more aggressively major-adjustments (2-6 turns) either direction, this did not change things -at all-.

Now here's the real kicker. When I first received the boat, I attempted a land start and realized that the black cover (four bolts holding it in) on the side of the carb facing closest to the port side of the engine was puking fuel into the engine bay. I removed this and properly resealed it. No further leaks at that spot. I then removed the spark plugs and cleaned them with brake clean and reinstalled them. This motor then fired, and for 2 seconds (before I manually killed the engine), it appeared to have full throttle control on land. Granted -- unloaded, and I did not watch the tach.

Does anyone have any suggestions? ANY help is greatly appreciated, I've spent most of the last week reading forums to no avail.

 

[CanuckJetter]

More testing last night....and I may be doing this incorrectly, so please let me know:

Removed plugs -- cleaned off, cranked starter to clear out cylinders for 5 seconds. Reinstalled and attempted start (no choke/throttle). No start. Repeated using choke/throttle alternatively a few times. Pulled wires and confirmed there IS a spark, though cannot quantify the quality of the spark. Kept rinsing and repeating, attempted start w/ starting fluid (pre-mix). No bueno. Could not get the engine started at all last night. Did have 2 minor backfire attempts where I thought it would catch, but didn't get it going.

Found spark plugs to be gapped to approximately 0.034". Regapped to 0.025".

This -MAY- be due to the redneck spark test I was doing -- however it almost appeared as though the spark was delayed by 1-2 seconds off of initial crank. Is this a symptom anyone has experienced? A slightly delayed spark may explain my issues (as fuel is flowing like the river Nile, flooding seems to be a valid concern). I'm starting to wonder if I should be somehow chasing down spark issue(s), though I'm unsure of where to begin. When checking against the port engine (and this could have just been a better connection during the test) it appeared that the spark had no delay (this engine also fires instantaneously every time with no choke/throttle).

Other notes, though I'm unsure of how valuable the information is:
*I've read about the "grey fuel line" somewhere, this carburetor still has a grey fuel line -- does not appear to be leaking
*Have not checked fuel filter (inside or outside of carburetor) -- does have the old school white plastic external fuel filter
*Dess key gives the "I'm attached" 2 beeps when plugging in -- haven't heard anything else from DESS

Any thoughts? Thanks! Really hoping to put the boat in the water for a Canadian thanksgiving trip before winterizing it .

 

[Barnhart501]

I’m certainly not a longtime pro on this forum, but I have owned a number of skis with that engine. My guess would be on your carb first. Your problem sounds fuel related. Sounds like you’ve been fairly thorough, but here’s my two cents…

When you reinstalled the black cover, are you sure you got it back together correctly? If there is a missing piece in the carb fuel pump, it won’t pull fuel in at all.

If it is put back together correctly, maybe it’s pumping too much fuel into the cylinders and actually is flooding them. This would be my guess. My first step would be to turn the fuel supply completely off for a bit and crank the starter intermittently. Make sure your fuel line is cut off, or you’ll just be pumping more fuel in when you crank and won’t get anywhere. That’ll dry out the cylinders and it may actually fire. After cranking on it (plugs removed) for maybe 30 seconds, shoot some starting fluid in the carb and see if it fires. If it does, I’m going to say you’re flooding the engine and need a carb rebuild.

I’ve tried this trick on a number of skis if I suspected they were flooding. Usually after cutting the fuel off, it would actually fire at some point because it had enough fuel to burn but not flood. Try it and see what happens.

 

[CanuckJetter]

Thanks a ton for the response. I have a sneaking suspicion that you are correct as well.

As far as that black cover goes...the gasket inside of it was hardened, so I softened it up with some silicone spray. I -did- silicone the edges of the cap to create a better seal (as I did not have a replacement for the rubber gasket at that time).

I'll give your idea a whirl and report back in about 6 hours from now!

 

[Russellbugg007]

I kind of experienced the same problem with mine It was very hard to start almost like it was flooded Turned out to be the pop off pressure.. I would take a look at the carb and double check that pop off pressure to make sure it's within specification

 

[CanuckJetter]

Status update! Apologies for the delay, didn't get to working on it until just now. I started working on Barnharts procedure, but began with removing the grey fuel line s I knew they need replacement due to being 20-some-odd years old. Turns out it was clogged full of blue smurf-beard. I replaced the line, blew out the black regulator and the supply side, and the engine fires right up instantaneously every time with throttle control. I added some fuel treatment to break up all the crap in there. I think I'll try it on the water now and see what happens on Wednesday!

 

[CanuckJetter]

Adding to this -- I can get the engine started every time now, but just compared the throttle "loudness" on land to that of the port engine and found that the responsiveness is very weak comparitively (doesn't throttle anywhere NEAR as loud). I wonder if there's any of that crud blocking it up still...or where to go next... she's bogged!

 

[CanuckJetter]

Second to last update (hopefully). Following the lead of you gentlemen:

I pulled the carburetor off today (holy crap...probably 10 minutes of actual work...easy for a first timer) and found the fuel/vacuum line that DIRECTLY feeds the needle at the top of the throat (sprayer) had a big hole in it. Carburetor kit is in the mail for tomorrow.

Tomorrow after work, I'll replace the two fuel/vacuum lines on the carb...clean it out thoroughly and use the rebuild kit. Hopefully that will do it! I'll check the pop-off pressure while I'm at it, of course.

Only questions I have:
*How often does the needle + seat have to be replaced? Usually good with a clean? They're difficult to find.

*What is the little black box that is lined to the fuel on the bottom of the motor? It appears to be some sort of fuel pressure regulator. Is there any merit to opening it up and trying to clean it up, knowing that the nasty grey fuel line that was full of schmoo runs directly from engine to it?

Thanks everyone!