Rinker/OMC ???'s

[Searchin']

G'day all,

I recently purchased an '88 Rinker Fiesta Vee 250, OMC 5.7L (260hp) and Cobra OD. The boat runs really well and the family has enjoyed the boat every chance we get to get her wet.

The only concern I have though is, at WOT. She will only pull about 4K rpm. I am looking to find the original prop specs that Rinker supplied the boat with. It currently has a 15x17 alum. prop. I called Rinker cust. service and their records only go back as far as '92. They also don't have any OMC information. The cs rep did mention that the Alpha's were supplied with a 16" prop. I have not verified what the ratio differences are between the two od's are.

So, I am hoping someone out here may be able help me find the correct prop info.

JFYI, I am the 4th owner of this vessel.

TIA,
Searchin'

 

[steelespike]

Re: Rinker/OMC ???'s

RPM and speed by gps would help.Is the prop in good shape?
If we can get a base line with this prop we can probably figure the best
prop from there.
You might want to verify the tach is accurate knowing the GPS speed at 4,000 will help with that if someone knows the ratio.The max recommended rpm may be on a label on the motor.You also may be able to borrow a shop tach to check the tach.That boat is a load at 4,600 lbs,do you have a lot of extra gear aboard?Were you running alone? Full tank?How many gallons.You might do a compression check at 20 years old could be a little tired.Be sure it is well tuned and throttle opens all the way.

 

[Searchin']

Re: Rinker/OMC ???'s

Sorry about posting in the engine section, thought i was still in the prop forum.

GPS ground speed = 32-32.5 mph on 6"-12" chop @ 4k rpm (trimmed/tabbed out).
Cruising @ 3500 rpm = 28.5-29 mph and 3200 rpm = 25.5-26 mph.
No Wake @ 1200 rpm = 5.8-6.1 (trim full down, tabs @ cruse setting).

Prop shape- Blunt edge but fairly smooth (I de-burred it), it has been repaired once that I can see (welded) and very small ding in 1 blade (fellow boater said that it should'nt affect it much).

Tach verified @ idle (Autometer 5" monster tach).

Engine- 270 hrs. Leakdown test results showed heathy cylinders. Very little case pressure out of valve cover vents. No film on flame arrester. Running regular 87 octane and timing of 8? initial and 20? @ 3000 rpm (no load), I have not had a chance to verify WOT timing. Both my OMC and Clymer manuals state WOT rpm between 4200-4600 rpm. The engine runs extremely smooth and quiet. New carb fuel filter (was clean), separator (no water) and new plugs.

Idle speed temp- 160?, cruising- 165?-170? and WOT- 170?-175?

I still need to pull the risers and check the exhaust flaps (I have read that they can come loose and cause this same problem).

I'm guessing sea weight to be around 5,500-5,700 #'s loaded. Required gear, 1/2 tank of gas (30 gls??), same rpm and speed with full tank, 15 gls fresh water and 2 adults (350 #'s combined), 2 kids (120#'s combined) and can't forget the cooler.

Thanks,
Searchin'

 

[Searchin']

Re: Rinker/OMC ???'s

Update:

OMC Cobra outdrive ratio- 1.41:1

I guess if I had read my OMC manual b4 the Clymer. I would have found my answer. The prop that is on it is for a bowrider/cuddy, part # 391200 (15x17). The one that is supposed to be on there is a # 391535 cupped 15 1/2x15.

So, I guess I've found my missing 400 rpm. Now off to get a new prop. Any suggestions as to what brand to try for?

Searchin'

 

[keylan]

Re: Rinker/OMC ???'s

Hi searchin we have the same boat with the same problem. We tried a 14 1/2 by 15. helped alot. BTW we are in West Mi too. We are slipped in Manistee but live in Newago

 

[Searchin']

Re: Rinker/OMC ???'s

Hi searchin we have the same boat with the same problem. We tried a 14 1/2 by 15. helped alot. BTW we are in West Mi too. We are slipped in Manistee but live in Newago

Hi keylan, nice to meet ya. We're down in Grand Haven/Spring Lake. I haven't slipped her yet, still working on things little by little in the driveway. Last owner didn't do any maintenance, just partied on it. Stopped @ my local marine supply and they had a new #391535 in stock! and for a good price!

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