Itty Bitty 4 stroke problemo! - need some mechvice

[TJQ]

Forgive me if I ask some stupid questions.. but other than my honda ive never dealt with a small 34 stroke.

 

Ok.. So I picked up a small 2.5 hp yamaha 4 stroke. MINT. Its been stored a while. It runs... but only really well when the choke is on so im thinking letting it run for a bit would help.. But I cant can really see where the water input in is (if there even is one)... I want to let it run, but dont want to mess it up by not having it in the water....... Help.. this is new territory for me and I want to make sure its running well before i take it in the bush.

[HTHM]

Got a barrel? Fill it with water and run it in there.

The water intake is usually on the gear housing above the skeg.

Edited May 1, 2013 by HTHM

[Fisherman]

If it only runs with the choke on, it needs a carb cleaning, some of the passages/jet are likely clogged up a bit. Most of the time all motors must be in the water to cover the cavitation plate for the impellor to push the water up. If there's no water coming out of the pee hole or exhaust, most likely need a new impellor. Good luck.

[mikemcmillan]

Is it possible that it is air cooled?

[tb4me]

Is it possible that it is air cooled?

That is what I was thinking too..

[Sinker]

I don't think yammy makes an air cooled outboard, but I could be wrong.

 

Run some seafoam thru it. It might cure your fuel starved problem.

 

Other than that, put it in water up to the cavitation plate and make sure its pumping water.

 

If it was me, I'd have the lower unit pressure tested, and new impellor installed regardless. Cheap insurance.

 

S.

[Old Ironmaker]

TJ

 

I did some google for Yammy 4 stroke 2.5 HP and came across some specs you might use TJ.

 

Cooling says water, thermostatically controlled so my guess that it might be air cooled is wrong as well.

 

I'll be back if I find anything else that may help. The heading did say 2.5 horse but I now see the specs say 2HP? here's the link, it has a picture so you might compare.

 

http://boatmarineasia.com/products/New-Yamaha-2.5-HP-Outboard-Motor-Four-Stroke-Portable.html

 

Product Description

Series: Four Stroke Portable HP: 2 Engine Type: 1 Cylinder Displacement: 4.4 ci (72 cc) Compression Ratio: 9.0 RPM Range: 4500-5500 Fuel Induction System: OHV Fuel Type: Unleaded gasoline (minimum pump octane 87) Exhaust: Thru prop Ignition System: TCI CARB Rating: 3-Star Alternator Outputat WOT: NA Starting System: Manual Lubrication: Splash Gear Ratio: 2.08 Control Type: Tiller Handle Trolling Throttle Adjustment: N/A Cooling: Water, Thermostatic Control Weight: 37 lb Gear Shift: F-N Command Link System: No Enhanced Ultimate Corrosion Protection System UCP: Standard Feature Power Trim and Tilt: No Shaft Length: 15 inch Gearcase Rotation: Right Hand (Standard) Stop Switch Lanyard: Yes Ultimate Corrosion Protection System: Yes 3 Year Limited Warranty: Yes Thermostatic Cooling System: Yes Aluminum Propeller: Standard Tiller Handle Steering: Standard

Edited May 2, 2013 by Old Ironmaker

[DRIFTER_016]

TJ

It's a thermostatically controlled water cooled OB.

Check for a water intake screen on the under side of the cavitation plate above the prop.

Pretty sure that's where it is on those.

It's in that area on my 4hp Merc.

 

Can't use muffs on them.

I used a 6 gallon pail to test mine.

Need to keep a hose running into the bucket though.

Edited May 2, 2013 by DRIFTER_016

[aplumma]

T.J. I would send a P.M. to Bernie and see if he has time to tear down the Carb. It needs a good cleaning and he can fix it quickly and test it for you as well. I would hate for you to get out on the lake at JJ and putter out. It isn't like there will be another boat coming along any time soon.

 

 

Art

[TJQ]

Thanks guys.. i put it in the barrel.. and ran it a bit its running without the choke on now, but doesnt like to idle down.. seems like the more i run it the better it gets. Hasn't kicked on the water pump yet. Ill try Bernie.

[Roy]

Start your motor in the barrel and run a short length weedeater line into the 'pee hole'. If it's blocked by dried weeds or mud, it'll all come out. If it still doesn't pee, stop the motor and get it checked.

[TJQ]

I think the problem is that the pump ius thermostat controled and i dont want to over heat the motor so im only running it in 3-4 min short bursts.. but theres no water discharge, so maybe its not warm enough, but i don't want to over heat it... kinda a catch 22

[aplumma]

The thermostat should not block all of the water it should always let some come thru. This is how my other 2 outboards work so I am ASSUMING that to work the same way. Bernie is the man for the correct answer.

 

 

Art

[Sinker]

I don't think there is a thermostat on that engine.

 

Mine says its a thermostat cooled engine as well, but mine has no thermostat. Its pumping water as soon as its running. Be careful if you have no water.

 

Like I said, I'd have that lower unit checked out. Seals and impellor anyways. Shouldn't be too much. I had mine done over the winter for $350, and thats a 40hp.

 

S.

[Fisherman]

Every thermostatically controlled engine has a bypass. It stays closed until it reaches the prescribed temperature and then opens for extra cooling. How do you thin you get heat in your car/truck, the bypass is the heater core, once the temp is up, then it also flows through the radiator.

[Old Ironmaker]

I don't want to hijack this thread but I have a question about the exact thing. Finally found a good crank battery to fit and put on the earmuffs yesterday and started my 115 merc. There is water coming out a pee hole next to the prop but once I started it no water at the shaft. I thought I should run it for a few minutes but am chicken. How long before it warms up? Does low water pressure/flow from the garden hose effect this? I think the garden line is plugged up a bit.

 

Going to launch tomorrow, crossing my fingers.

[Fisherman]

Holes next to the prop are not "pee" holes but drain holes if the interior of the leg has water in it. The water goes in at the intake, up through the impellor to the engine and cooling ports and out either the "pee" hole and/or the exhaust. Some models have a small exhaust port above the water line. Some engines take longer to warm up, depends on the temperature of the lake water or the cold water from your hose. Low hose water pressure shouldn't matter too much, it's the impellor pump that provides the pressure to get the water up to the motor. After all in the lake, there's no water pressure.

[Lunker Larry]

agree with Roy. Check the simple things first. If i was stored you may have a spider or something blocking the pee hole. Poke around with some soft wire or weed eater cord first. Be agressive, you won't hurt anything.

[DRIFTER_016]

Could be a malfunctioning flux capacitor.

Have you checked the gamma feedback relay?

[irishfield]

Hey TJ... don't mess the gem up! Run it down to Bernie's Brothers at Giesler Marine...... I dropped my 5 horse Honda there in March, as I couldn't be bothered to tear into it myself and wanted it fixed right. Total go over.. new impellor.. oil changed top and bottom.. carb overhaul.. tank tested and purring like a kitten for $200 and change ready to pick up on our way North next week!