GT150 Problems

[wtp]

Re: GT150 Problems


we'll I think i got it to idle. The low end timing was so far off. I'm trying to adjust it but it won't adjust according to the manual. I need a link n sync for dummy's. Here is what I did. I made sure the butterflies are all the way closed. and retightend the "C" screws (I letter my adjustments) and made sure the roller was centered on the first line on the large cam. Then it tells you to set your low end timing to 7 +/- 1, my cover on motor says 4 to 6 BTDC. it says if I'm reading right to use the thumb screw I have lettered "E" but mine only opens the butterfiles by turning that because your pushing the cam farther down which in return opens the butterflies. If i understand this right it should mover the timer not the butterflies according to the book. Am I right. The only way I can get the timer to move is to adjust the throttle cable where I have letter "D". BTDC should be to the right of the TDC mark Right? I did do the step where it shows you how to set your TDC pointer and that was right. This link and sync is confusing the heck out of me. When and if I ever get to the step where you adjust your high end spark the book says 32 degrees +/- 1 and my cover says 28. Which one is right? I'm just trying to get everything close (not the max spark) so it runs ok on muffs and then I'll put it in the lake and adjust everything the correct way but If I don't under stand it now it don't pay for me to be on the lake trying to figure out the adjustmens. Any directions in layman's terms would be great.

 

[j_k_bisson]

Re: GT150 Problems

You first need to remove the throttle linkage from the remote controls from the motor linagages. The E and G screws are the ones that you should be playing with. The G sets your minimum idle. The E screw sets the timing. I would loosen the G so it does not impeed you timmer from traveling down. But remember how far you moved it. For reference later. (Like 4-5 complete turns) Then adjust the E screw to get the idle timing you are looking for.

H is you WOT max timing adjustment.

Hope it helps. You should be in the 5-6 degree range for idle, at a spec RPM's.

 

[wtp]

Re: GT150 Problems

ok, thank you - I'll give that a try tonight when i get home providing it isn't raining. Thank all of you again for helping me out. I could take it in and have it fixed but what do you learn from that? nothing. Thanks again and i'll post my results.

 

[wtp]

Re: GT150 Problems

the motor seems to run ok so far. I left it on the trailer and backed it into the river with throttle cable diconnected and set the low to 4 degrees BTDC. and it's running about 900rpms. little high but way better then before. the tach is a used tach I picked up so I hope it's good. Book says 7 +/-1 and motor says 4 to 6 and I got mine at 4. Now max timing in the book says 32 +/-1 and motor says 28. I set it at 32 and it is running about 4500 rpms. Once it warmed up I didn't need to choke it anymore it just fired right up. Hope it stays that easy to start. Does anyone know if my settings are right or will they work?

 

[wtp]

Re: GT150 Problems



3 questions - 1st is my settings right for the timing in previous post? 2nd I was told my motor might be sitting to low to get top speed. Bottom of my motor to the bottom of my boat is approx 22". 3rd would a bigger pitched prop do me any good with only 4500 rpm? It's a 15 x 17. If it would, would size prop would be a good one to try?

 

[j_k_bisson]

Re: GT150 Problems

That 900 rpms is a bit high you might want to lower that to the 650-750 range. I think that you will possibly grind the gears in the lower unit at that higher RPM over time. The shift interrupt switch will not drop the rpms down enough if left the way it is.

JMO

 

[wtp]

Re: GT150 Problems

If I drop it down then I'll be less than 4 degrees. Does that matter? Any idea on the rest?

 

[j_k_bisson]

Re: GT150 Problems

Ok

#1) The timing is set to the rpm's. For my motor it is 650-700 rpm's at 5-6 degree timing. If you power head stickers are calling out 6-7 degrees then it is that at 650-700 rpms. Not 900 rpms. You need to play with it some more.

#2) The motor height does play a large role in top end RPM's. Mine I had to raise it 2 times to the 3 bolt hole to get it right. Basically you want the top cavitation plate even with the top of the water that comes off the hull at plane. If not you are loading/causing axcess back pressure in the water that the motor has to over come. Learn't that one from my local dealer.

#3) I would not increase the prop pitch as the high the pitch then the lower the RPM's at WOT will go. If you decrease the Pitch you will sacrafice speed for higher RPM's at WOT. What is the WOT rpm's for your motor?

 

[wtp]

Re: GT150 Problems

I'm at 4 degrees now and it's running 900 rpms. It does not grind into any gear. It is alittle high I can tell just by listening to it. My max rpm for the motor is 4500 to 5500 rpms. cover over the carberators says 28 degree max spark but book says 32. I have it at 32 to get 4500rpm. Is there something off that I'm at 4 degrees for idle and at max 32 degree for 4500rpms?

 

[wtp]

Re: GT150 Problems

been doing alittle reading and I might have this wrong. Am I suppose to be setting this stuff in forward gear? My settings are in nuetral not in gear.

 

[wtp]

Re: GT150 Problems

I got it to idle pretty good. no need to choke the hell out of it to start it. starts right up. sputters alittle when you take off. hits 35mph (still not good enough for me) motor won't trim and only hits 4300rpm set at 32 degrees max spark. As far as the trim it's full of fluid. works out of water but not in the lake under power. The sputtering, I'm not sure carbs are spottless and floats are set right and put new plugs in again. 4300rpm, who the hell knows. all out of ideas once again.

 

[j_k_bisson]

Re: GT150 Problems

If it is sputtering it could be one of two things. One being fuel. Try pushing in the choke. If the sputtering stopps then its fuel. If it does not then its your timing. I think you might have the timng a bit low. Might want to bring it up to the 5 degree mark then retry. Also I would check the max advance if the motor has on setting on it and the manual has a different I would go with the motor one. You can be burning up your motor if it is not set right. I would reconfirm your manual matchs your motor. Is it a factory manual or after market?

 

[wtp]

Re: GT150 Problems

motor says 28 at 5000 rpm. I can't get 5000 rpm. nuetral or driving the best I can get is 4300 rpm and the prop is a 17p. my idle is 800 rpm at idle in gear. the sputter is when I'm accelerating from a stop. doesn't sputter idleing.

 

[j_k_bisson]

Re: GT150 Problems

Then you have the same problem that I have. You are over loading the motor with your prop selection. From idle to 2000 rpm I have a medium shutter if I try travelling at that RPM. After that RPM the motor take off like road runner. Beep Beep. I dropped from the 17P prop down to a 15
P prop and most of it clearded up. But it is still there in a smaller zone of rpm's. I talke to the dealer and he recommended drill the prop to induse some slip at this rpm. Her also stated it would not effect top speed much 2-3 MPH. But your hole shot will suffer. Your prop will slip and the loading of the motor is be decreased. But how much I do not know. I have reservation drilling into my prop! Don'\t have the money to buy another one. Been watching EBay for a cheap used one to play with first.

 

[wtp]

Re: GT150 Problems

what about the rpms. I can't get 5000 to set my spark at 28 degrees.

 

[j_k_bisson]

Re: GT150 Problems

The reason you can not is your pitch on your prop is to high. If you drop your pitch then the rpm's go up. Bass boat guys do this. The get the pitch of the prop to the highest they can get it and sacrafice their mid rpm range. In my motor with the Fixed jetting they start playing with the jeting to clean up the mush/shuttering.

If you want to set you top wot spark advance use Joe Reeves method. Its spot on acurate +/- 1 degree most of the time.

 

[wtp]

Re: GT150 Problems

UPDATE:

I still have not got this motor to run right. To many things are not adding up. One day runs "ok" next time trolling motor has more power. 2wks ago i decided screw it, it wasn't working the way it was so I tore it down. Pistons, cyclinders and crank all look good. Bought OEM powerhead gasket kit, 2nd set of needle n seats (OEM this time) and new mid and high speed jets for the carbs and new fuel check valves. Got it back together and it did run but leaked alot of water right below the power head. I did put a new gasket in there but looks like it might be just a little lower than that. I'll hopefully know more today (8-13-11) cause I'm pulling the power head off again to see if maybe the gasket is ripped or something. Will post results. Oh and this motor has been ripped apart once before. There was 2 newer pistons in it. did kinda look like there was poor sealer between crank halfs. looked alittle thin in areas and possiable traces of leaks.

 

[wtp]

Re: GT150 Problems

My fault,power head to exhaust gasket was in upside down. Motor runs pretty good just can't get the low idle adjusted right. I'm gonna try new plugs since the motor has had all new gaskets put in. The plugs I put in were from when it was running crappy. They were new and only have maybe 1hr on them but I'm gonna put champion in. Boat is running 35mph at 5200rpm. I've never had rpm like that. Motor sounds good, rpm good and speed sucks but I'll play with the prop once I get everything dialed in.

 

[j_k_bisson]

Re: GT150 Problems

Sounds like you speed/rpm is good. I hate to read thru all this but what kind of boat/weight are we talking about.

As to idling, its all about three things. One the orfices in the throttle body plate, the carb orfices being clean and air leak free in the bowls and fuel lines, and then timing. How did your linc and sinc go? It took me three times to get it just right. The first time was just to figure out what every screw and adjustment did. LOL

Good luck you are on the home stretch. It just takes a bit of time and hair pulling to get it just right. And even then you will still be tinkering with it........

 

[wtp]

Re: GT150 Problems



Boat is a 17' 1986 Hydra-Sports. I need to redo the link an sync this week. All jets are new in the carbs. top end is pretty good, not as fast as I'd like but will play with that when I get it dialed in. My main concern is getting the idle / low end timing set. I raised the motor 1 hole and that brought my rpm's up to 5200. Yea the link and sync took me alittle bit to figure out. Still don't have it but I understand (I think) how it is suposse to work. I'll know more this week.