1998 Speedster Twin 787, Low RPM Problem

[dbwilson]

Bought a used Speedster in Spring. Engines both started fine, took the unit out on the river and found the Starboard side engine wouldn't put out. Looked at the fuel and air supplies and looked on this board for answers. General consensus on low revs is fuel and air. Changed the plugs, fuel filters, cleaned the RAVEs (thanks for the postings on those, they were gunked pretty bad, but still moving a bit), and fresh fuel at recommended 87 oct, oil is Merc 2 cycle.

With changes, trying it in Neutral in the garage, both engines start easier, sound better, and run smoother, but I rev to 3800 RPM in Neutral (very briefly) and have half the throttle left on either engine. Is this because there is a Neutral rev limit coincidentally at the same speed that I was limited to on the water in forward gear? Do I need to get it back on the water to see if my tune-up worked?

If this doesn't work (filters, plugs, RAVE), what else could it be?

Another clue...at very first try, the Port side engine would rev to 6500 and only the Starboard was bogged, but last time they both bogged.

They just don't sound like they are lacking air and fuel. They sound/feel like they're being limited.

 

[timmyboy76]

hey wilson...your right about the "limiter" in Nuetral, wont let it rev above 3500. While on hoe, throw to "F" position, then it'll rev up, if not, then inspect the button on that limiter assy, under the levers' assy...

 

[fatboy666]

how can I use this to ask a question....my seadoo xp 97 keeps cutting in the water....Ideas....thx

 

[timmyboy76]

how can I use this to ask a question....my seadoo xp 97 keeps cutting in the water....Ideas....thx

i'd start with carbs, fuel selector, inline filter..etc.

 

[dbwilson]

hey wilson...your right about the "limiter" in Nuetral, wont let it rev above 3500. While on hoe, throw to "F" position, then it'll rev up, if not, then inspect the button on that limiter assy, under the levers' assy...

OK, so I woke up this morning and had a thought: why is the engine running well, sounding like it's getting fuel and then gogging down coincidentally at the same RPM as the Neutral limiter? Anyone want to to a stab? <grin>

I noticed that the shifter is super-stiff, and that the covers for the nozels don't totally clear the nozels when shifted into forward. I'm thinking that there may be a couple problems: 1) as you mention above, I have to have a look at the limiter assembly; 2) I need to lube the shifter cables.

I will look at the manual, but I tried to remove the shifters one time and got stumped and reattached them. I recall it looking difficult. Anyone have further advice?

Really hoping that this is the problem, and thanks again for the info.

 

[dbwilson]

question

hey wilson...your right about the "limiter" in Nuetral, wont let it rev above 3500. While on hoe, throw to "F" position, then it'll rev up, if not, then inspect the button on that limiter assy, under the levers' assy...

What does while on "hoe" mean?

 

[timmyboy76]

fat fingers..

What does while on "hoe" mean?

While, you have the "hose" attached and motors running, wit hwater going thru it....

Remove the 4-panhead screws on top plate of lever assy, the nremove the 4-allen panhead/countersunk screws under that plate, which in order to remove the plate, you'll need to remove the 3-lever knobs (2-red, 1-black), then top plate will exit. Reomove the 4-allen heads, the nlift assy strate up...

 

[dbwilson]

nothing seems wrong there

While, you have the "hose" attached and motors running, wit hwater going thru it....

Remove the 4-panhead screws on top plate of lever assy, the nremove the 4-allen panhead/countersunk screws under that plate, which in order to remove the plate, you'll need to remove the 3-lever knobs (2-red, 1-black), then top plate will exit. Reomove the 4-allen heads, the nlift assy strate up...

Other than the shifter being unusually difficult to push into forward position, nothing seems wrong there. If the boat thought I was continually in Neutral I would not have been able to start it as it doesn't start when out of Neutral. Lubed everything I could see in the shifter area. I guess I have a nasty corroded shifter cable. Really not easy to see where I would lube the cable, I guess you don't.

So if I still can't get more than 3500 RPM out of the thing in forward, what next?

 

[timmyboy76]

on/under lever assy, on f/n/r/ side, you'll see a flathead, black plastic screw. Loosen that up, see if that helps with lever motion. Its a tentioner for that lever, another one on other side, for starboard throttle and the "chrome" panhead screw in middle of assy, is for port throttle. Spray wd-40 on all that crap there, to help loosen/lube...

 

[dbwilson]

on/under lever assy, on f/n/r/ side, you'll see a flathead, black plastic screw. Loosen that up, see if that helps with lever motion. Its a tentioner for that lever, another one on other side, for starboard throttle and the "chrome" panhead screw in middle of assy, is for port throttle. Spray wd-40 on all that crap there, to help loosen/lube...

Tried that, just reassembling shifters now. We're good for looseness and lube in that area. The problem is the shifter line being tight and I'm looking for the position/tension adjust on the nozel covers....when shifted into forward the covers don't come off completely, I have to push lightly on the covers directly and they "click" open. I assume that this might not be a prob when the water is flowing. Real issue is getting that shifter cable loosened up.

I shifted into forward whilst idling, and then gave some throttle....got the ring-ding-ding very quickly, and it started toward +5000 very quickly. I don't think the low rpms are a problem because of the shifter now. Gotta get on the water to recheck the loaded revs.

Thanks a lot, buddy, have helped me along with the tech and confidence as I work this AM.

 

[dbwilson]

Tried that, just reassembling shifters now. We're good for looseness and lube in that area. The problem is the shifter line being tight and I'm looking for the position/tension adjust on the nozel covers....when shifted into forward the covers don't come off completely, I have to push lightly on the covers directly and they "click" open. I assume that this might not be a prob when the water is flowing. Real issue is getting that shifter cable loosened up.

I shifted into forward whilst idling, and then gave some throttle....got the ring-ding-ding very quickly, and it started toward +5000 very quickly. I don't think the low rpms are a problem because of the shifter now. Gotta get on the water to recheck the loaded revs.

Thanks a lot, buddy, have helped me along with the tech and confidence as I work this AM.

On another topic, where can I get a "out of production" engine/storage cover? I see they make them for 2004 models, and that the 1998-2004 were all the same. Make sense?

 

[dbwilson]

Still having tough time with starboard engine revs

Tried that, just reassembling shifters now. We're good for looseness and lube in that area. The problem is the shifter line being tight and I'm looking for the position/tension adjust on the nozel covers....when shifted into forward the covers don't come off completely, I have to push lightly on the covers directly and they "click" open. I assume that this might not be a prob when the water is flowing. Real issue is getting that shifter cable loosened up.

I shifted into forward whilst idling, and then gave some throttle....got the ring-ding-ding very quickly, and it started toward +5000 very quickly. I don't think the low rpms are a problem because of the shifter now. Gotta get on the water to recheck the loaded revs.

Thanks a lot, buddy, have helped me along with the tech and confidence as I work this AM.

So I had it back on the water. After cleaning 3 of the RAVEs (one of the four seemed nice and loose and I skipped it rather than pull it), changed the fuel filters, and doing a general clean-up, the Port side engine is fine. Throttle up revs to 7500 RPM. Starboard side still has a problem: it runs a bit rough higher than 1500-2000 RPM, and if I give it WOT it revs to 7500 RPM briefly, then slows and stalls if I don't bring the throttle back. Starts quick and idles well, I can throttle up to 2000 RPM with a smooth running engine, if pushed to 4000 RPM it sputters and dies. Sort of feels like I have a plugged fuel line and it allows a small flow but when it tries to draw more fuel can't keep up and then dies. How/where should I start tracing this problem?

PS: The RAVE I skipped is on the problematic engine, but with the cap off it moves in an out freely. Could that be the sole problem?

 

[timmyboy76]

i thought mine were "free" until I removed them from housing, just to find they were saturated/tarred up with carbon...

 

[dbwilson]

i thought mine were "free" until I removed them from housing, just to find they were saturated/tarred up with carbon...

...and the one Rave contamination would cause the throttle reaction the way I described? I guess I have to get rid of the variables, but it really felt more like fuel restriction.

The other ones (3) were severely carbonized....like Han Solo carbonized, but I thought the movement was the only issue, and got lazy (fricken rear units are a pain in the ass to remove).

PS: Thanks for the continuos engagement Timber!

 

[timmyboy76]

lol...yup, looked at the mag side raves, and f-it, thought because they moved, they were free. Not the case, and in your case, if the other 3 were Hans up, then you know the 4th one is.:cheers:

 

[dbwilson]

keeps getting better, but no joy

lol...yup, looked at the mag side raves, and f-it, thought because they moved, they were free. Not the case, and in your case, if the other 3 were Hans up, then you know the 4th one is.:cheers:

Both engines running better. New fuel inlines, all 4 raves cleaned, back on the water, better running, port side cool, starboard side will run max 5000 RPM if at all, loses RPM sounding like fuel restriction. I can get it to 7000 RPM briefly, but then it dies and I have to lower the throttle or it will stall.

One question I have is why the RAVE guilotine has the flat side to the cyllider port rather than the curved side. Is it possible this is wrong?

I really think I have a fuel restriciton somewhere, but can't figure out where, and I'm gun shy on popping the flame restrictors because I already broke the first bolt head off on the Port side. What next?

 

[mattyc75]

just had this too i fixed it

in each carb is a small pencil tip sized fuel filter. Try replacing them or checking to see if small dirt particles have clogged it/them. Pulled mine out and sure enough one had that. I replaced them with new ones and ran like a top till i just popped an oil line. good luck. There a pain but worth it.

 

[dbwilson]

in each carb is a small pencil tip sized fuel filter. Try replacing them or checking to see if small dirt particles have clogged it/them. Pulled mine out and sure enough one had that. I replaced them with new ones and ran like a top till i just popped an oil line. good luck. There a pain but worth it.

what is the basic procedure to get at these filters? in the manual?

 

[timmyboy76]

db...with all these post, not once, was cleaning the carbs, was mentioned...:ack:

 

[mattyc75]

db

Go to the parts page for your boat and look at carburetors. Part number 22 is the tiny fuel filter that I am talking about. Like I said mine has sand sediment in there and ran awesome after I put new ones in.

 

[dbwilson]

db...with all these post, not once, was cleaning the carbs, was mentioned...:ack:

So you still think it's the RAVEs?

 

[timmyboy76]

it'll only take about 15 minutes, to find out/clean.

 

[dbwilson]

it'll only take about 15 minutes, to find out/clean.

Glad you're on line Timber, I am anxious to get started today.

I did clean all of the RAVE valves (last one yesterday morning), per your instruction above. The last feedback I gave was after final RAVE and taking the boat back on the water.

Things are getting better, but still have startboard side surging and dying. Just sounds like it's running out of fuel, then either dies or if I bring throttle back it might stay idling. Seems to only be under load.

What do you think next?

 

[timmyboy76]

fuel lines, inline filter o-ring bad, tighten all fuel line clamps, clean fuel selector, was the rv manifold removed, and if so, was the rv set back at right degree...:cheers:

 

[ski33]

may be air lock!
remove the arrestor covers and put your hand over the top of the carbs and get someone to crank the motor for about 10-15 seconds it will pull your fuel up fast and remove any air traped in there!
long shot but it s just a thought!