prop size

[edjr]

anyone know what the correct prop setup would be for a suzuki dt140 on a 17 ft bass boat, shop says its overpropped it acts like its loading up with 3/4 throttle..... wont go 20 mph?????? any other suggestions what it might be???

 

[edjr]

Re: prop size

anyone????/

 

[DJ]

Re: prop size

edjr,<br /><br />The last DT-140 (1995)I owned ran best with a 13" X 19". That ran it at about 5800 rpm's at wide open throttle (WOT).<br /><br />Without knowing your WOT rpm's, we're guessing.<br /><br />If it only runs 20 mph, I would say the engine is sick. Not unusual for the carbed DT-140's to plug up a Mikuni carb or two.

 

[edjr]

Re: prop size

just got it out of the shop they said they cleaned the carbs he took it out on the water ran about 4000 rpms (guessing tach doesnt work) so he said he thought it was overpropped thats why it isnt getting the rpms

 

[DJ]

Re: prop size

edjr.<br /><br />First off, you have to have an accurate tach.<br /><br />Second, what is the pitch of the prop now?

 

[edjr]

Re: prop size

i have a tach on order and the the prop thats on it is a 22

 

[rodbolt]

Re: prop size

2nd thing is a dyno run with a known good tach. I dont think suzuki offered many test wheels. if they did, a run on a test wheel with an inductive tach is in order. you must confirm the engine is capeable of making power before playing with props. especially if you just bought a rig and have no idea if it ever turned the correct RPM with any prop. you would not believe how many sick motors I have seen that the sickness was "corrected" for by altering the prop. usually sick motors die. unless they are made well again some die rather rapidly others a long expensive death. its just to quick and easy to verify engine power output first.. its also a good time to compare the hull tach to the shop inductive tach.

 

[edjr]

Re: prop size

ok thanks for the info ill call tomorrow to find a reputable service shop ( i think the one in our town is kinda shady ) and see if i canted get it tested. atleast the dealer gave me a little bit of a warrenty on the mechicanics of the boat, would the motor still run really good at idle and low rpms if were sick?

 

[edjr]

Re: prop size

i live in northeast oklahoma we dont have a dealer that has a dyno machine...is there any other tests that can be done to be sure that the motor isnt sick... has good compression #1 cyl 140<br />#2 135 #3 135 #4 140...good spark...getting gas and oil ok...but is only getting about 2500 rpms at wot.. has a 13 1/4 x 22 prop..is there any truth to a fine line of correct pitch that if you get overpropped that youll lose rpm's??

 

[rodbolt]

Re: prop size

yes.<br /> it can be sick and perform well at low speed. your call.<br />but with no way toload the engine its almost impossible to test correctly.<br /> keep hunting for a test method. maybe Fridays marine will see this and have a test wheel suggestion. mercury marine years ago gave a spec to cut up an aluminium prop for testing purposes at wot while tied to the dock. we got a copy of it at a suzuki fuel school years ago. I have not seen mine in years.<br />its either over propped or sick. the cause must be determined. need to verify health before installing new props. there is no "standard" prop.

 

[edjr]

Re: prop size

i called the dealer that i bought it from and we agreed that i will just get my money back... he felt i shouldnt have to have this many issues with buying it from a dealer,, thank you all so very much for your help it held alot of weight in my discussions with him on what could be wrong..