1989 120 Looper stalls at part throttle

[jy118lfd]

I just got back from running this. Or at least trying to. When running in water if I put it in gear and bring the thottle up to part throttle or just into the intermediate jet it runs for about 30 seconds and then dies like it runs out of fuel. I just took apart the 4 carbs and flushed the orfices from the main jet well to where the emulsion tube picks up the fuel for the intermediate circut. No restrictions. I also flushed all other orfices they are clean. I am at my wits end. I also cleaned the throttle plate ports. Am I missing something???<br /><br />Joe Reeves Dhadley???<br />I know this motor is different than my crossflow but c'mon its all the same air fuel spark and compression

 

[Dhadley]

Re: 1989 120 Looper stalls at part throttle

Youve still got the airbox cover on, right?

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

Yes I will only idle it with it off<br /><br />One more thing I just checked another set of carbs I have all carbs are 398743<br />The other set the throttle body has 4 transfer hole by the throttle plate the ones in the motor only have two. If I give it a little throttle and look in the throat I do not see fuel coming out of the holes in the throttle body.<br /><br />I see that the 91 uses a 27 air bleed for the mid and the 89 that I have uses a 50 maybe I have a mix and match carb set? <br /><br />I never ran this I got it used and you know It RAN great he said.<br />Compression is 120 on all 4 no variation

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

I may try the other throttle body I have or get 4 27 jets and see if that fixes it. <br /><br />Throttle body in my shed is 334872<br />4 transfer holes

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

??

 

[Brew2]

Re: 1989 120 Looper stalls at part throttle

Hi Jon,<br /><br />Been chasing basically the same problem with my '86 140 for a loooooong time now. As a temporary solution so I can at least get going, I bump the primer just before or during acceleration. The extra shot of fuel seems to get me "over the hump". Once running on the high speed jet everything works great. <br /><br />Since I've cleaned my carbs numerous times and never found a problem, I'm sort of assuming that I have an air leak somewhere in the fuel system, but so far have had no luck finding it. Replaced all the hoses, gaskets, clamps, etc. and still have the same problem.<br /><br />I assume your experimentation with the different intermediate jets didn't help seeing as you appear to still be seeking assistance.<br /><br />Sorry I don't have a solution....please let us know if you figure it out. If I don't figure my problem out this spring I think my wife might just try sinking the boat with me in it!!<br /><br />Good luck.<br /><br />Brew

 

[Dhadley]

Re: 1989 120 Looper stalls at part throttle

Jon & Brew -- how many screws in the side covers on the carb body?<br /><br />If the carbs and throttle bodies are a mix-n-match set you may be in for a long test session with a box of jets. <br /><br />Lets look at the side plates first.

 

[Brew2]

Re: 1989 120 Looper stalls at part throttle

Hi Dale,<br /><br />My rig is still tarped with a foot or so of snow on top of it....going to be a few weeks before things melt enough that I can get back at it.<br /><br />Going by memory, all the side plates on my carb bodies have two screws. All the jets are original size per the factory manual. <br /><br />Jon....sorry, didn't intend to "highjack" your thread. Hopefully Dale will have some suggestions that we can both use.<br /><br />Cheers,<br /><br />Brew

 

[Dhadley]

Re: 1989 120 Looper stalls at part throttle

Since you're both looking at similar things I don't think anyone will mind but it is Jon's thread.<br /><br />The side plates on those carbs are kinda notorius for pulling in air. It'll give you all kinds of fits. They ususlly suck air at idle but can at any point. Pull the plates off and make sure they're flat. Make sure the rubber gasket is good. Replace it if there's any - any - doubt. <br /><br />Then look at the float level. It's gotta be right. There are a couple of carb body castings. If you thought the float setting was odd or strange in any way this may help. One casting needs the plastic washer under the seat, one doesnt.<br /><br />If you put one where it doesnt belong or leave it out when it should be there, it will seem like you have to bend the float arm a lot to get it parallel.<br /><br />Anyway, one casting has a slight raise where the seat screws in. That casting does not use a washer. The other casting is flat and requires a washer. <br /><br />Ok, lets think about this a while before we go on the jetting.

 

[TD_Maker]

Re: 1989 120 Looper stalls at part throttle

I had the same problem with my 89 88 spl. I made the big mistake of purchasing a fuel line at Wally World with one of those universal pump balls. ran great at idle, but it would bog down and surge at speed.<br /><br />When I finally looked at the new fuel line, it actually appeared smaller that the old line I just replaced. Went to an Auto parts store and purchased 15 ft of 1/2 inch fuel line, put on the old pump ball, and it took care of the problem.

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

Dhadley my problem is not a bog before acceleration. Mine will not pull fuel through the intermediate circut on all 4 carbs. I have a complete set of carbs and throttle bodys that I got from a friend and I know they were off an 89. I looked at my carbs and they are the same part number but the throttle bodys are different. I see the only difference with the throttle bodys are the ones currently on the motor have two holes by the throttle plate and the ones from the known 89 have two larger holes and two smaller holes. I would seem to think that the two holes would produce less vaccum to the intermediate circut than the 4 holes. They all go into the well where the welch plug is on the throttle body.<br /><br />If the 2 holes are from an 91 or later I can understand it as that model used A 27 intermediate air bleed and would require less vaccum to pull fuel out of the well and the 89 uses a 50 air bleed that would need considerably more vaccum signal to pull the fuel instead of pulling air alone. <br />Again I have a problem on all four not a single carb pulling air from somewhere wich leads me to believe mix mathced components <br /><br />Brew a bog before acceleation could be a link and sync issue I would start with that. My problem is not a bog but that if left at part throttle for a few seconds the motor stalls. If I run at idle or into the highspeed jet I do not have a problem.<br /><br />I am switching to the carbs and throttle plate from a known 89 and will post today with the results.I did not try the jets as I would have to buy them.<br /><br />Dhadley when I got this motor I noticed that the jets in the intermediate circut were all over the place as one was 14 one 27 one 24 and a 41. <br />When I was going over the motor I found 3 bad check valves and figured someone screwed with the jets to cover up the problem. So I returned all to stock when I was in there.<br /><br /><br />SORRY for the long post I just wanted to be clear on my problem<br /><br />Brew no problem on posting your problem in here I hope my problem will help your solution

 

[Dhadley]

Re: 1989 120 Looper stalls at part throttle

On yours I was concerned about the float position. It's very important on a looper. Much more sensative than on a crossflow carb. A good known matched set a great place to start. before you install them look at the side plate. Are you going to transfer your kits over to them?<br /><br />I agree that the set you have on is a mess. Once we get the motor running correctly we may be able to go back and do some jetting although I hate that. The carbs need to stay with the matching throttle bodies.<br /><br />Also make sure the emulsion tubes (vertical tubes in the carb throat) are perfect. Some will fall apart.<br /><br />If youre going to clean the good set and put kits in, let me know. Thers one more trick we like to do in that process. If you've already got them clean and ready to go, don't worry about it. It's only worth doing if you're already in there.

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

They are cleaned alread but I will take them apart to check the float like you said. Two screws hold the side plate on. What do you want to do in the carb cause I am taking them apart to check the seat gasket if it needs them or not

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

I hate to rejet cause without a dyno and exhaust temp or air fuel meter you don't know what you've done.<br />I know I put the gaskets under the seat but I don't know if it needed them

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

The other throttle bodys did it!!!!! It now does not stall and draws fuel into the intermediate circut. <br /><br />I forgot to metion before on my flowscan when idleing it was at 1.5gph and when you gave part throttle it went to .8 then .5 and stalled. Now in a tank no load when at part throttle it goes to 2.5gph so I know it is drawing fuel.<br /><br />Dhadley I had the gaskets in and did not need them I took them out and readjusted the floats. I see what you mean about the adjustment.

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

I will post the results of my sea trial in here and in the other prop topic.

 

[Dhadley]

Re: 1989 120 Looper stalls at part throttle

Cool beans! Glad it worked out. Keep us posted!

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

It runs good about 1800 rpm and lower it has a intermitent miss comes and goes it idles but is rich until 1800 then smooth as silk right up to wot<br /><br />5600 rpm 38.5mph 13gph 30 psi water press<br /><br />The motor is way to low av plate is under water at wot evidenced by spray and able to trim full and rooster tail with no loss of bite<br /><br />What can I do about the idle and low rpm richness? Will raising to motor help that as there will be less backpressure?

 

[jy118lfd]

Re: 1989 120 Looper stalls at part throttle

Any Ideas on the low speed richness? <br /><br /><br />I checked all the floats and had to lower them and will try it again on mon.<br /><br />Is it normal to have rejet the ldle air bleeds on these????