• This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.

1998 Sportster 1800 port side motor wont start! Out of ideas!

Status
Not open for further replies.
G

griscy2581

New Member
So this is my first year with this boat and have been running it most weekends this summer with no problems at all. Took it out a week ago and ran like normal, but a week later only the starboard motor will start. It has spark, I believe it is getting fuel (also directly put some gas in the intake and even cylinders), also did a compression test and both cylinders read 125 psi (i believe that is low, but didn't think that would stop it from starting). Motor only turns over, never fires, not even for a second, even with the direct fuel supply. I am out of ideas. Any input would be appreciated!

717 motors.

Thank you,

Jason
 
Your compression is fine.

Pull the plugs, choke off, wide open throttle. Crank it for 5 seconds and repeat (total of 10 seconds of cranking). Install brand new plugs. Make sure the plug wires are not mixed up. Crank for 5 seconds. Spray a 2 second shot of starting fluid into the air box. Crank for 5 seconds while changing the throttle position. Spray 2 more seconds of starting fluid and crank it again. Clear the cylinders again, change plugs, add more starting fluid.

Pouring gas into the cylinder or carburetors is not as effective as starting fluid. Gasoline in a liquid state is not flammable, so your relying on fumes to form in the engine. Starting fluid is a vapor, which is very combustible, and will more effectively start the engine. Also, its very easy to flood the engine if your pouring gas into it. A flooded engine wont run any better than a super lean condition.
 
Ok, I went through the sequence and after spraying the starting fluid in the air box the engine fired very briefly. That is the first time it has done that, so that is progress. I cleared cylinders again and it fired very small again, but only after the clearing each time, not if I try the starting fluid for a second time. What does all this mean?

Also, does the fuel pump supply both motors? If the other motor runs fine, can I rule that out?

Any more suggestions?
 
It definitely sounds like a fuel issue. Currently you are in the diagnostic stage, so the only thing your looking at is whats between the air box, and the exhaust manifold. The fuel pump is of no concern until you can get the engine running on starting fluid. You are either still flooded, or too lean. Try changing the spark plugs out and giving it a 3-4 second shot of starting fluid, if that doesn't work, increase the amount of starting fluid to 5-6 seconds.
 
Keep in mind that the spark plugs will tell you a lot about whats going on with the fuel system. If your crank is full of gas, the plugs will come out soaking wet. If you are way too lean, the plugs will always come out bone dry.
 
Does your boat have oil injection working? Starting fluid provides NO lubrication, and will also "rinse" the oil off the cylinder walls if you are not carefull. 125 psi of compression is on the low end so if you do find your problem you should look into a top end before it eats its self and you need a bottom end too. If you have a lean carb issue it could be why you have low compression. Each motor has its own fuel pump. To narrow down your issue you could swap carbs between your two motors and see if the problem follows the carbs. If your compression tester is reading high say by 15psi then your real compression is 110psi then you are asking for a new motor to keep running it, so you should also check compression with a different gauge.
 
I hope the oil injection is working, at least it should be. I did check the other motors compression and it read 140 with the same guage. So I agree it could use a top end, I just don't understand why this is happening yet. I like the carb sway idea. I suppose I will try that too. Thank you!
 
Having 125 lbs compression is not going to cause the engine to "eat itself". People on this site keep saying that low compression is going to cause a melt down, and its just not true. Having low compression may cause the engine to stop running if its below 100lbs, but thats all. Low compression is a symptom of a problem, not the cause of a problem. If you run out of oil, the engine will have many problems INCLUDING low compression. Low compression will not cause you to run out of oil. Low compression is not going to cause the piston to melt. Low compression is not going to damage the crank. Low compression is not going to cause the head bolts to strip out. Low compression is not going to cause the steering wheel to fall off.

Yes, its true that starting fluid does not provide sufficient lubricant for extended run times. Running your motor for 5 seconds on starting fluid is not going to damage anything. If you can get it to run for 5 seconds on starting fluid, then move on to the carb or fuel filters, and fix the problem. Starting fluid is just used for testing, not cruising around the lake.
 
People keep taking their engines apart and find major problems, and they think it was all caused by low compression. Low compression is caused by other engine problems, not the other way around. A melted piston skirt and shredded cylinder wall is not caused by low compression. If you overheat that cylinder, the piston expands and get forced against the cylinder wall. The lack of clearance causes extra heat to build up, and the skirt gets rubbed off/melted. Once that happens the compression drops. Compression loss is a SYMPTOM, not a cause.
 
Last edited by a moderator:
To clarify what I said to the OP, if your carbs on your problem motor have a issue that causes the engine to run lean, that MIGHT be why you have low compression reading on that engine. I did not say that your engine is going to eat its self because of low compression. Your compression tester has shown you a warning sign that you have a problem in your motor, in turn that could cause a melt down from a mechanical problem. If you do have something come apart in the top end and it takes out your bottom end, you will wish you did the top end before it quit running all together. Once again I did not say low compression will cause a melt down, I am saying what ever has caused your low compression CAN cause your top end to come apart and destroy your crank. I'm sure that your head bolts, steering wheel, and oil level will not be affected by running the motor with low compression.
 
Thanks guys. So I ran the cylinder clearing sequences again a few times. During which, I see a steady mist of what I am assuming is fuel being blown from the cylinders each time. After that I proceed with a few seconds of starting fluid into the airbox, then with no choke and no throttle hit the start button, each time it fires for a half second, then not again till i clear the cylinders again. I have tried choking and some throttle after each initial try and nothing. After removing the plugs, they seem pretty dry, but its hard to tell since they are new. Should I move on to swapping carbs or fuel pump or what?
 
One way to find out for sure if its running lean, is to remove the spark arrestor, and start cranking it over. Now, while the motor is cranking over, spray a solid stream of starting fluid directly into the carb. That will provide PLENTY of fuel for it to run. Its not the ideal way of doing it because it can backfire through the carb, but it works. Its possible that the crank is full of fuel, and clearing the cylinders is leaning it out just enough to run for a second. If there is mist shooting out of the spark plug hole, then it either has too much fuel, oil, or water in the crank case. There should not be a mist coming out of the hole.
 
Well, I took the airbox off sprayed a couple seconds of starting fluid into the spark arrestor and it fired up then stalled. I tried again with some throttle and it started. Sounded rough but it ran for 10 seconds before I shut it off. After I noticed a nasty black looking mixture of water/oil/fuel was sprayed out of the exhaust when it finally started. Any ideas what that was from and if it is a sign of something?
 
The water/oil/fuel is of no concern. You can run it for a minute or two without overheating. Keep checking the temperature of the head with your hand, and run it some more. Don't overheat it. Try to get it to start without starting fluid, and rev it up a few times to see if it will settle down and run normally. It may take a few minutes of running to clear the crank out of all the extra fuel that may be in there.
 
It worked! Starts right up as usual. I still don't know if I understand why it happened or what exactly happened? Seemed like clearing the cylinders then the starting fluid shots did the trick. Now lets just hope it all works fine in the water. I appreciate all the help, you guys were great!
 
Glad it worked out for ya. If a motor fails to start in the future, pretty much all ya got to do is check the compression, check the spark, and do that same starting fluid technique while checking/changing the plugs often. 4 stroke motors are a little more complicated, because they have valves that can be out of time, but they run on the same principle, and with the same starting fluid procedures.
 
Ok, one last question as to why this problem happened. Is is possible to flood an engine/crankcase by moving the throttle back and forth while the engine is NOT running? I do have 3 kids, and that could very well have happened even though I didn't see it happen I definitely wouldn't rule it out : )
 
griscy2581 said:
Ok, one last question as to why this problem happened. Is is possible to flood an engine/crankcase by moving the throttle back and forth while the engine is NOT running? I do have 3 kids, and that could very well have happened even though I didn't see it happen I definitely wouldn't rule it out : )
Click to expand...

Yes it is possible to flood an engine/crankcase by moving the throttle back and forth

It is also possible the engine floods because a leak in the carburetor...specially on warm starts. (10 mins-90mins after shut down) Just do you best to figure out if it's rich or lean start and adjust accordingly.

Too Much fuel, leave Throttle wide open and crank away...it will start..bogging down first, very rich, then starts. (If no start, Pause between attempts I would not crank over 10 seconds, and take a long pause.)
Too lean(rarer, but it can happen) pump throttle fully one time, leave at idle or just above and crank. If no luck, pump and open slowly as you crank. BAM, starts right on if you Accelerator pump is working

If you guess wrong it takes forever to start in the wrong fuel state with the opposite technique. Best to have carbs in perfect shape for easy starts. (Leaky valve you can postpone fixing a few weeks. Lean Carb state must be remedied immediately or sooner or engine can be damaged)

Let it ride for the next outing or two being observant of how it behaves, them make your decision on whether carb service is needed. Could have been the kids messing with the lever. Mine (port) is leaking now only when anchored in very rough chop. Takes about 20-30 seconds of cranking total when it happens. I'm about to switch to my new carbs today on that one engine.

Good Luck!!!
 
Status
Not open for further replies.

Similar threads

N
97 Speedster Starboard Motor won't run
Replies
22
Views
645
kenneth.mccoy1
K
Ed Clark
BN CARB FUEL PUMP EXPERIMENT - Point of Interest Only
Replies
7
Views
114
Ed Clark
Ed Clark
AJF22
Motor cranks, but no run till it’s given a sniff of cleaner
Replies
0
Views
181
AJF22
AJF22
andy.262
97 GTI wont start
Replies
3
Views
236
andy.262
andy.262
L
  • Locked
1998 Sportster 1800 - Can only run one engine at a time?
Replies
2
Views
594
lauramsportster1800
L
Back
Top