Speedster- non standard starting problem

[AusSpeedster]

Thanks in advance everyone.

I have been reading lots of posts for weeks trying to troubleshoot but havent managed to solve my issue.

I bought a twin engine speedster (787’s) that had a port engine that would sometimes cut out randomly. It would sometimes start back up, but more often would take 5-15mins of cranking (giving breaks between each try to avoid over heatin the starter) and then would run again for 15-45 mins without a problem.

I rebuilt the carbie because i knew the previous owner had only used it 3 times in 3 years so i thought it may be gummed up, but i found the carbie was immaculate unlike other seadoo jetski carbs i have rebuilt previously.

The problems started after i rebuilt the carbie. The engine no longer starts at all, or even cranks for very long.

I thought i had over worked the starter with all the cranking, so I have replaced it with a new starter. That didnt fix it, still wouldnt crank.

I swapped the starter solenoid from the good engine over. Now it cranks, but not for very long, then after a few tries it wont crank.

I tested the battery, puts out over 350cca, but found the voltage dropped to 7v while cranking, so i replaced it with a new 780cca battery. No voltage drop when cranking but it will only crank for a short time, sometimes wont crank.

I thought it might be a bad earth so i ran an extra 8g earth lead, didnt change anything.

I dont get a beep at all from the DESS but i think thats just the buzzer, ill replace it but it hasnt worked the while time.

I have also ordered 2 starter solenoids just in case its still the solenoids.

Ill also try bridging the starter switch to see if the switch is an issue.

Any other thoughts on what i can check or test? The engine turns very freely by hand with the plugs out.

I have also replaced the rectifier to hopefully solve the random cutting out of the engine that started this whole problem.

 

[racerxxx]

If your voltage drops below 10vdc while cranking you'll get no spark.

 

[AusSpeedster]

Thanks for the reply racer, but with the new battery the voltage isnt dropping. Still stops cranking after a short time.

 

[AusSpeedster]

Quick update- i replaced the buzzer and im getting two beeps when attaching the key so thats sorted. However i had a strange thing happen

The starboard engine will crank easily and the voltage only drops a little, the port engine often wont start cranking even when i bridge the solenoid. It also arcs with a LOT of current when i bridge the solenoid compared to doing the same on the starboard engine.

Again, the engine turns very freely by hand with the plugs out. Why would the new starter draw so much current and not always crank the engine? Should I have greased the starter before installing it? Is there anything else that could cause the starter to struggle on just 1 engine?

 

[mikidymac]

Either a bad junk starter or bad cables. Remember the cables go bad from the inside.

 

[racerxxx]

I would swap the starter from the good engine. I ran into this exact same issue before but it ended up being the battery. The starboard would turn over effortlessly and start right up. The port engine starter would engage and stop or barely turn the engine over. Replaced the battery never had the issue again. I'm the original owner to the boat. There is a ground that runs from mag housing to mag make sure that is clean, I think it serves more common ground between the separate engine electronics rather than having a possible floating ground back to the MPEM...possibly, but it could help bridge in the event the port ground cable is bad going to the starter. Make sure the starter grounds are good and clean. It could be the cables but these things rarely see water inside them like skis do so........but worth a check. It could also be the replacement starter. %0 is your starter ground cables and 99 is the one on the mag housing. Pull the battery and charge it

 

[AusSpeedster]

Thanks for the reply guys. Ill check those over and I had another thought today. Could I have been given an incorrect starter that has the wrong anount of teeth? From memory there are 2 types and i dont remember checking that (i only checked the length and bolt positions)

 

[AusSpeedster]

So after a bit of research it shouldnt matter if i installed an 8 or 9 tooth starter as both should work, its just the gear ratio that changes. Ill put in a new battery, solenoid and check the grounds. Could the positive wire also cause issues?

 

[AusSpeedster]

Hey racerxxx, do you have any more info on the “ground that runs from the mag cover to mag”? Is it shown in your picture?

 

[racerxxx]

Yes, bottom left #99 it's just a jumper wire about 16" long

 

[AusSpeedster]

I see it, thanks for that. I dont think its my issue though

This morning i put in a new 680cca marine battery freshly charged, and installed it then ran new 400amp jump cables from the battery straight to the starter. Again it would crank for a few seconds then stop. As soon as it stopped you would see the jump cable teeth heat up from the excess current.

I think im going to have to swap out this brand new starter.

 

[AusSpeedster]

I swapped out the new starter this morning and the symptoms were the same.
This afternoon i pulled the plugs and cranked it. It spun very easily but i had a very dangerous situation. Lots of fuel sprayed from the pto side spark plug hole, more than the mag side i think and it seemed excessive. It was only a few seconds and was extremely dangerous as it sprayed it right near where i was shorting the solenoid to crank the engine. PLEASE DONT TRY THAT ON YOUR ENGINE for obvious reasons

Once i have the new solenoid in Ill run a similar test with a tube in the spark plug hole but I think I may have messed something up when rebuilding the carb which fits the timeline of these problems.
Can anyone think where the problem may have been? Any weak links in aftermarket carb rebuild kits? I rebuild 2 carbies on a 951 engine before and it ran perfectly for the year before I sold it, but I may have overlooked something. This carbie had the fuel pump seperate.

 

[mikidymac]

If it’s flooding that will cause the starting problem as you can’t compress a liquid.

Absolutely the aftermarket carb kits are junk and always cause problems.

Too stiff diaphragms and crap needle and seats cause flooding.

Replace with genuine mikuni kits and needles and seats.

I wish we could embed a warning in the site that says no aftermarket carb kits whenever you visit. Would cut the threads in half.

 

[AusSpeedster]

Just wanted to update this for anyone searching in the future
The issue was hydrolocking from me stuffing up the carb rebuild. This also caused fuel to be pushed down through the crank case and so the rotary valve needed to be removed and new seals put in.

Done now and running