4HP 4 stroke Yamaha, stalls past 1/4 throttle

[country_bumpkin]

Have a 4 HP 4 stroke Yamaha (2000 model, a kicker on my 22' sailboat). Starts easy, runs well at less than 1/4 throttle, but when I try and turn is past 1/4 it stalls........(it will rev up past 1/4 in nuetral though)

Took this to an independent mechanic, told him the problem, he rebuilt carb, replace spark plug, replaced water pump and serviced lower unit...to a tune of 368 bucks. Thought that was expensive.....anyway when I tried to start it back on the boat, I couldn't....I realized the choke was discontected, I reconected the cable and got it to start. Again, it started easy ran well under 1/4 throttle.

I complained and he said he would come and make an easy adjustment, would take him 3 minutes, well that was 3 weeks ago.


I could haul the engine back to him, but he's not too local. Also, I thought if it was on the boat it I could test it under load.

Question: is this just an easy adjustment? Can I do it myself? I'm pretty mechanically inclined.

I was out yesterday, it was very windy, could have used the extra power.

Thanks for your suggestions.

CB

 

[rodbolt]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

your still describing a lack of fuel in the cylinders, can be from a restriction,bad fuel pump or most likly still trash in the carb.
for high speed there really is no adjustment.

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

your still describing a lack of fuel in the cylinders, can be from a restriction,bad fuel pump or most likly still trash in the carb.
for high speed there really is no adjustment.

Thanks Rodbolt,

So, is it likely that this "mechanic" never rebuilt the carb?

The engine was spotless when I brought it to him, so it's hard to tell if he actuall did any work on it.

I did check the oil, it seemed clean, but don't know if someone changed it last season (I bought the boat last July)

 

[rodbolt]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

cant answer that question.
its a simple carb but the passages are incredibly small making them really hard to clean.
but your describing a dirty carb or lack of fuel in the fuel bowl.

 

[Yamajoe]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

Sounds to me like the main jets have crud. The jets and orifices need to be carefully cleaned and have compressed air blown in through them, your mechanic may have done the job although i have my doubts, but crud could have been still in your fuel system and worked its way into your carb again, it happens all the time. I would change your oil and filter as well if you are not sure when it was last done.

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

Thanks all, one more question, this is a simple engine, like a lawnmower, right? I'm pretty mechanical, brake jobs, water pumps, radiators, tune ups on cars.......is this something I can tackle? or leave it up to the pro's? How about with a manual?

I originally took it to a mechanic because I have never worked on an outboard before, but he probably charged me half what the motor is worth, just to "get it ready for the season"

CB

 

[Yamajoe]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

Get yourself the right manual for this motor and you will save heaps - it is daunting to start with as you would know workng with the unknown but with patience and some basic tools it is a lot of fun i reckon anyways.

 

[TheFin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

I would change your oil and filter as well if you are not sure when it was last done.

There is no oil filter in that motor (F4).

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

Thanks for all the input.

I emailed the mechanic twice last week, nothing. So I call him today...and he agrees to meet me out at the marina tommorrow, "an easy adjustment", but from what y'all tell me here, there is no adjustment for this situation.

This will be interesting. I'll let you know if he shows up, and if he does, whether or not he can fix this with an adjustment.

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

Thanks for all the input.

I emailed the mechanic twice last week, nothing. So I call him today...and he agrees to meet me out at the marina tommorrow, "an easy adjustment", but from what y'all tell me here, there is no adjustment for this situation.

This will be interesting. I'll let you know if he shows up, and if he does, whether or not he can fix this with an adjustment.

Well, the "mechanic" never showed, long story.

Got a service manual 2 days ago and then:

I opend the motor up and checked the oil, dirty. Checked the plug, old. Drained the carb, crap came out. Then I removed the carb, cleaned it thorougly with seafoam and compressed air, reassebmled and started it up.
It jumped when I reved it. Jumped like it's never jumped before. BUT! gas came squirting out of the top of the carb. I quickly realized I put the float in upside down and assbackwards. I flipped it back around and started it again, it hesitates and stalls again. This tells me that something is wrong with the amount of gas filling up the bowl, right? Can I bend the float a little? The pin looks okay.

Any advice would be great, oh and this all took me about 1.5 hours. Here is what he billed me:

Remove,rebuild carburator: 3.0 hrs-$195.00
Carburator rebuild kit: $13.97
Replace Spark Plug: $2.38
Replace waterpump,new seals,refill with Yamaha fluid,pressure test: $125.00
Remove,clean fuel tank,replace: .5 hrs- $32.50
Total: $368.85
Method of payment is cash with no sales taxes applied.
Warranty is for 30 days on all parts and labor.

btw, I can't find a carb kit for under 35 bucks.......

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

bump

 

[country_bumpkin]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

For anyone that reads this thread, here is a lessson learned:

Yamaha manual on disc from Ebay: 10 bucks

Having your beautiful wife clean your jets and nozzles in an ultrasonic cleaner at the orthodontist's office where she works-priceless (heh heh heh)

Running top notch now.

Can't believe I gave that loser 370 bucks


ultrasonic for these small jets!

CB

 

[azlakes]

Re: 4HP 4 stroke Yamaha, stalls past 1/4 throttle

... good to hear you got it running. its a great feeling to do the work yourself and gain success. that mechanic(barely) is a scum bag.

how does that 4hp push your sailboat around? i am looking at a 2.5 hp for my 16' scanoe and 12' raft.