new intermittient problems

[jlr40]

After searching the forums for "the answer" i see that a few others have the same problem i am having and noone has answered so heres is my wierd variation...

Today, after a few weeks of great boating, starboard engine dies after 10-15 mins of 3/4 trottle. Engine starts back up no prob, but bogs and dies. If I sit for for a few mins, engine starts back up and will run again for 10-15 mins. I check raves, oil, fuel, filters, and plugs, nothing out of the ord. Finally got frustrated and went to the bar. After an hour of sitting in the water, cranked engines to dockm, slammed throttles and got 7000rpms from port (norm) and a whopping 3100rpms from starboad. Acceleration didnt seem to be abnormal, except for the bogged down motor. I also tried to rev the engine and it would not rev past 3100ish. Checked everything again, plus weedless, again nothing out of the ord.

Limped back to dock, got home and plugflushed engines and both purr like tigers, and rev'ed purrfectly fine. GDit, I am very frustrated now. I am thinking maybe jetpump problems, but to me it doesn't make sense.

This is my first jet boat, but I know more about skis (they seem easier, but a two year old cant ride them much). Just bought the boat a month ago, and when I winterize I am going to pull the carbs and rebuild them.

Any suggestions would be great, and all recomendations for reliability for next season are greatly appreaciated.

Thank you in advance, Josh

 

[CypherAZ]

After searching the forums for "the answer" i see that a few others have the same problem i am having and noone has answered so heres is my wierd variation...

Today, after a few weeks of great boating, starboard engine dies after 10-15 mins of 3/4 trottle. Engine starts back up no prob, but bogs and dies. If I sit for for a few mins, engine starts back up and will run again for 10-15 mins. I check raves, oil, fuel, filters, and plugs, nothing out of the ord. Finally got frustrated and went to the bar. After an hour of sitting in the water, cranked engines to dockm, slammed throttles and got 7000rpms from port (norm) and a whopping 3100rpms from starboad. Acceleration didnt seem to be abnormal, except for the bogged down motor. I also tried to rev the engine and it would not rev past 3100ish. Checked everything again, plus weedless, again nothing out of the ord.

Limped back to dock, got home and plugflushed engines and both purr like tigers, and rev'ed purrfectly fine. GDit, I am very frustrated now. I am thinking maybe jetpump problems, but to me it doesn't make sense.

This is my first jet boat, but I know more about skis (they seem easier, but a two year old cant ride them much). Just bought the boat a month ago, and when I winterize I am going to pull the carbs and rebuild them.

Any suggestions would be great, and all recomendations for reliability for next season are greatly appreaciated.

Thank you in advance, Josh

When was the last time anyone went thru the carbs? or rebuilt them?

 

[jlr40]

what i was told...

when I bought the boat, the owner told me that the starboard engine was new to the boat and the port was the original. i have no clue when the carbs have been cleaned, but at the end of the season, ( or my season, whichever first), i am rebuilding both carbs, so I can rest easy that they have been done. Carbs are first on my to do list, but my problem just doesnt feel like a carb issue, then again my wife says my 'feeler' sucks!:stupid:

 

[CypherAZ]

time for a compression check, if it comes out good.....i'd think the issue would be the carbs.

 

[jlr40]

Compression good.

checked compression, both cylinders a little high at 155-160 psi, but held compression great. guess i'll start pittl'in with the carbs. BTW, the carb rebuild kits sold at sbt, for the 787 motor, do i need to buy two kits per motor or does one kit rebuild both PTO and MAG? Besides the carbs can you think of anything eles to look at?

I think i forgot to mension that there is a slight vibration coming from the starboard engine, but only at 3000-5000 rpm, (when the motor was running fine), after the boat got up on plane the vib stopped.

Thanks you everyone for any comments or suggestions.
--Josh

 

[jlr40]

here i go again

going out to troubleshoot on the water guys, wish me luck. hopefully i get some advice while i am out there since i got wifi on the phone laterz. thank you

 

[timmyboy76]

beat'n a dead horse

either winterize it now, or take the day off, beat'n around the bush, and tear carbs off. Its only the one motor, so you sound mech enuf. That job, no more, should take 3hrs, plus pull the raves and clean them.

 

[jlr40]

i love you guys!!

thanx for the slap in the face timmy...

but that doesnt help when i am already on the water..

heres the update... pulled off pto rave and found that the retention spring broke. i used stainless wire to wrap the bellow to the blk plastic thing...saw that the pto spark plug had overheated, prob due to the bellow falling off, changed that. now i am running 50mphs all day with no probs...knock on wood.

timmy, i do really need to pull the carbs, but i want to rebuild them and i kind of need to know if i have to buy one kit per enegineor two kits. the description says the kit is for one carb. soooo, i need two?

thank you all...i am kinda hardheaded, and i appreicitate you guys for keepin me in check.

laterz

 

[jlr40]

loads of fun

Well we are back in...i think i am going to take the advice and rebuild now. i think i know the problem, now i have to find out the cause. i am running hot and lean, (well if you run lean, your going to run hot. right). So while i am chasing that problem, i'll pull the carb. throttle response to the port engine is sluggish and when i ride WOT, port doesn't peak unless i hit wave hard enough to dislodge whatever the hell is choking it, so I will gladly eat my words apologise to world and take my slap down like a good obeying child!:banghead::banghead::banghead:

 

[timmyboy76]

depend'n on where you go...most are "per carb" price, to ther tune of 50 buks-ish EACH...:ack:

Pull the carbs, get few bottles of carb cleaner, count the turns "clockwise" on each high adjuster and low adjuster, til bottomed out. Then remove then, counterclockwise, replace the o-rings on them, from Ace Hardware, remove the needl/seat assy, replace the o-ring around it, and the rest of carb, break it down, and spray away.
After that, break apart the xcellerator pump, clean the little fuel lines and pumper with carb cleaner, then lube the pumper w/ any type grease, then re-install everything. $hrs, top chief, and at a tune of 5 buks...:hurray:
NO NEED FOR KITS....:cheers:, great going with the RAVE finding.

 

[jlr40]

Cool...

unfortunately I need the gaskets b/c I am afraid to pull anything off of the block. A month ago when I bought the hole, first thing I did was inspect raves, what happend is the hole got deep quick when the rave assemble gasket disentegrated into a mushy powered. So I have been reluctant to pull anything else off until my cash flow steadies up a little. But I think a i am going to bite the bullet and pull the carb, and at least clean and pop-it.

I am going to cross my fingers and hope that this cut is only a flesh wound.:lurk: