|
#1
|
|||
|
|||
175 Opti acting up... PLEASE HELP!!
I have been having trouble with my 2005 175 Opti for a few months now. Often on my hole shots it will rev up to about 2000 rpm then fall on its face. When it does this I usually have to try it at least 2 more times before it will finally get up and start accellerating. I have done many things to troubleshoot this to no avail...
1- replaced the plastic fuel line from the bulb to the motor. This line did have delamintated plastic causing some blockage, but replacing it dod not help. 2- took it to merc dealer to hook up the diagnostic tool to it. Showed no recent faults. 3- I have ran about 80 gal of fuel through it mixed with Quickleen at a ratio of about 1 bottle to 25 gallons of gas just in case it was caused by carbon build up or dirty injectors. 4- changed plugs and wires. The ones I replaced looked to be in good shape, but replaced anyway. 5- In the interim, I had blown out a fuel pressure regulator, so when I was troubleshooting that problem, I did resistance tests on all fuel injectors, direct injectors, coils and triggers. Also cleaned and inspected the FIs and DIs, and tracker valve. BTW... tracker valve diaphragms work great to replace FPR diaphragms; just need to put the new tracker valve dia. on the hub of the old FPR. 6- Inspected the reed valves. All are intact, but a few looked to be outside of the .020" stand open tolerance, but not too bad... have a new set of chris carsons coming because I don't want to run the chance of my motor eating those stainless reeds going forward. 7- Drained, but did not change the water separating fuel filter. Everything looked clean, and no water came out... was already after hours when I was at this step or I would have just bought a new one and replaced. Any ideas?? Any help would be much appreciated!! As an aside... I also have troble with the fill cap on my under cowl oil tank leaking oil. I tighten it down, and it just pops loose again. Seems to me like there's just too much pressure being applied and the cap pops off when the engine temp warms the tank enough. I did change the check valve that goes to the remote oil tank. This is the second tank and second check valve I have gone through. |
Sponsored Links | ||
Advertisement | ||
|
#2
|
||||
|
||||
Quote:
|
#3
|
||||
|
||||
After finding the partial blockage in the fuel line the filter is the first thing I would have changed. Hopefully it is something easy and cheap like that. Let us know what you find.
__________________
"This hunting, This is not a sport, right? It's not a plaything. It defines who we are. It's our heart and soul. It's something that trancends a lot of things in our lives." Quote from Rob Olson Delta Waterfowl President |
Sponsored Links | ||
Advertisement | ||
|
#4
|
|||
|
|||
Here's some ideas...
I agree with phowler- change the fuel filter for a start. Next, take a look at your tank pick-up to see if you've got a load of crud or flakes of tank blocking the intake screen due to alky attack from crappy gas. While you're doing this, replace the line from the tank to the bulb- checking very carefully the anti-siphon valve in this section of line if one is used. I'd also invest in a second new bulb because sometimes even new ones are bad. You might even try removing the anti- valve temporarily for a quick test, or re-routing the line such that it never falls below the top of the tank- and then running with no valve. I also assume you've got a full shop manual and you've done a link and sync on the throttle pick-up point. If it still runs bad- try replacing the TPS- you may have 1 or 2 of these. Lastly, the oil tank on the motor has a cap designed to be finger tight- if you turn it to tight the thread pops- that's why it just has a little ridge on top- you are supposed to use fingers only and it only needs enough torque to compress the oring a bit. You could try finding a new oring at home depot or a hydraulics house- since Merc doesn't sell the oring as a separate part. With a new clean and dry oring your cap might still be good- if not you must change the tank out again. By the way- I've had to add oil to this side tank exactly once since 2002 on my Opti 150- after I had the cap pop on the threads from too much finger torque. One last thought- on all the fuel line changes you've done- are you swapping to plain old steel hose clamps- or an electrical tie wrap? If so, remove all that you've changed and run to the nearest OMC dealer. They sell really nice 360 degree contact plastic clamps in a bunch of sizes that seal fuel lines perfectly. I keep about 2 dozen in my tool box at all times just in case- and use them on both marine and carbed auto engines.
Doug |
#5
|
|||
|
|||
Quote:
As far as the oil reservoir, I think I may have fixed that problem. I still had the old tank and the only thing that was wrong with it was that the cap never stayed tight. So, I just installed a 1/2" x 13 helicoil and a stainless bolt. Ran it hard last night and did not have a problem at all. However, my remote tank looked pretty bloated... is this normal? Seems to be a lot of pressure. Also wanted to give you guys some more info about the way it is running: 1- when I finally get it to wind up, the hole shot seems a little sluggish, but when it gets up on plane, it runs flawlessly. Would blockages in the fuel supply cause it to run poorly at wot? It seems like there would be more fuel demand at wot than during the hole shot. Or is the vacuum at higher rpms high enough to overcome any partial blockages that I may have? Maybe just answerd my own question there... 2- I have less trouble with it bogging down if I take off with the motor trimmed up. If the motor is trimmed all the way down, I can almost never get it to wind up. Sometimes I even need to turn the wheel sharply as I punch it to get it to wind up. I really appreciate your help. Brandon |
#6
|
|||
|
|||
More Info
the link and sync requires feeler gages and special bits for a hex drive to remove anti-tamper fasteners. The procedure is in the shop manual under throttle linkage adjustment and TPS adjustment. If its not a fuel system blockage then it could well be eithe a bad TPS or a bad tracker valve in the injection system. Both require the dealer's equipment to check out. The oil tank is under pulsed pressure from the crankcase, so it does swell a bit when the motor is running.
Doug |
#7
|
|||
|
|||
OK... checked the fuel pick-up screen, hoses and bulb. Screen and hoses were clean and in good shape. Pumped the bulb up and it held its volume; however, after I ran it for a while, I could always pump it up more. I'm assuming this is normal because I can always start it without pumping it. I also changed the fuel filter. Nothing has changed, though... still having issues getting it to wind up with the moter trimmed down or from partial throttle. I'm going to check the adjustments on the throttle linkage as described in the timing and synchronizing chpter of my manual. There are only two adjustments that can be made on my motor according to the manual - throttle cam adjustment and maximum throttle. Beyond that, I think I'm going to need to take it to the shop and have them do a fuel/air pressure test.
|
#8
|
|||
|
|||
My 150 Opti....
...if left for a week will only take about 1/8 of a single bulb squeeze to be firm. When running, its always firm. You should have someone try pumping the bulb firm while you're trying to hole shot the boat to see if the problem goes away. Also, the throttle cam adjustment is very critical. When you're in neutral can you freely spin the throttle roller?- it should be riding in a depression in the cam with a specific clearance. If not- then everything will be screwed up since the TPS assumes that the zero point is at the throttle stop setting- this stop is also
adjustable as is max opening, but the cam should be re-positioned first unless someone had messed with the throttle closing point set at the factory. Also, as I noted, the idle stop screw must be contacting the engine block firmly on the throttle lever with motor in neutral. Doug |
#9
|
|||
|
|||
OK... made the adjustmets to the throttle linkage. Prior to changes, the clearance between the throttle arm and the stop with the shift/throttle lever fully forward was a little over 1/4". Adjusted it per instructions down to .020". Also needed to adjust the throttle cam slightly. Took it out to the lake afterwards and was stil having trouble, although not nearly as bad. In fact, it would eventually take off about 10-15 seconds after bogging down. Before, it would never take off once it bogged. I will work with the priming bulb next. I'm thinking that it's not staying full at all times, especially after turing the engine off, because the times that I have tried pumping it proir to starting the engine, I've always been able to get in a squeeze or two. I do recall that it was firm the times that I tried pumping it when the engine was running. If there was a partial blockage in the pulse operated fuel pump, how would the engine behave? Also, how would the engine act if I had slightly low air pressure or a failing air pressure regulator? I know my tracker valve and fuel pressure regulator are OK as I just inspected the tracker valve and replaced the FPR.
Last edited by h2ofowl; 08-25-2010 at 12:18 AM. |
#10
|
|||
|
|||
You need to check the fuel psi at the vst when this is happening, I'd bet the fuel psi is droping and that would mean the boost pump is bad in the vst. I have had to replace alot of them with this same problem. Rick
|
Thread Tools | |
Display Modes | |
|
|