Muffs vs Barrel vs Lake?

[LionHeart]

Hey guys! I'm pretty new to the forum, and have already learned so much. I'm also new to outboards. I recently bought an 86 Johnson 15 hp, and have been performing a bit of maintenance here and there trying to get it running properly. I hope to have everything back together by this weekend, and would like to test it out in my driveway before putting it in the lake. I bought a set of muffs, and while I have a basic idea of how they work, I don't feel comfortable using them until I know a little more.

I'm pretty sure I can't take the motor to high RPM using only muffs, but just how high can I take it safely? Just Idle? What if I use a barrel? I guess what I'm looking for is a basic tutorial and run down of what a noob like myself should be aware of while testing an out board in the driveway. I've tried watching youtube videos, googling, and the search function here, and really haven't found what I'm looking for.

Any tips and/or advice you guys could give about using muffs vs barrel vs lake would be very appreciated. Thanks -James

 

[xXOnyxXx]

i never run a motor up in the rpms in a barrel or with muffs .... cycle the gears and maybe a lil above idle but if ya crank it up with muffs it has no load on the motor and is freewheeling, not good .. and ya will blow the water out of the barrel when revved up in gear ..... so to really test it take a ride!!

 

[timsmcm]

You can be a little more aggressive that that. Crank her and if she is running at low RPM good, let the motor warm up for a good while. Then take her up in the RPM range a few times but don't hold it there. Just wick it a few times to see how she responds. Now I don't mean top rpm, 2500 to 3000 but only after a good warm up.

 

[wmk0002]

Lake > Barrel > muffs.

You can probably safely rev the motor up a little of 2000 rpms on muffs but keep in mind that it wont really tell you much as there is zero load on the motor. You could have bad compression, weak or no spark on a cylinder, and a number of other issues that you may not be able to notice as they would be covered up by having no load working against them. For example, I have a 1982 Evinrude 15hp that idled and revved up well in a barrel and on muffs but wouldn't go past 2000 rpms on the lake due to an ignition problem.

At least with a barrel though you can put it in gear and try to dial in the low speed/idle mixture screw and the forward idle speed before heading to the lake. With smaller motors you can also cut a barrel so that the rear half of the top remains so that you can keep water from sloshing out and rev it up a little higher in gear.

 

[Stumpalump]

Use the muffs and give it a bit more water pressure than you think it needs. Not so much that it blows the muffs off. Watch the tell tail constantly. That's the little hose on the bottom of the cowl that pisses water. That tells you your water pump is working. Garden hoses get kinked. The hose pops off of the plastic muff coupler. The couplers pull out of the muffs. The muffs slide or vibrate away from the water inlet. You step on the hose and pull it. The prop catches the hose. All these things will make it loose water pressure so watch the tell tale constantly. 3000 RPM only sounds like a super fast idle. Don't wind it out. Two strokes rev quick and will zing to 8000 in an instant. Keep the dog away. They play with the water and get hit with the prop when you throw it in gear. Buckets and barrels work but you have to get the motor in before you fill it. It drains in an instant when you throw it in gear so you have to keep the hose in it. Of course it constantly flops out. I like muffs better. Never run it without water. You will melt a dry rubber water pump in 3 seconds running it dry. Not even a quick dry start is OK. Jet skis do it but they have a different pump. Have fun. That's a great motor.

 

[DaleH]

Muffs - Personally I don't trust muffs and city/town/local water pressure enough to put any RPMs to a motor due to no load conditions and lack of exhaust back-pressure .. and then pile on the RPMs and you can have a bearing failures or other.

Muffs will tell you it starts - or not - and that there's water peeing from the tell-tale hole (of which some do not route through the block). I don't ever put RPMs to motors on muffs, but that's me.

Barrel - You can test/check a little more here, like a t-stat opening by monitoring head temps with a laser temp gun or TempLStik, but like another posted opined, I personally stay well under 2,000 RPMs ... at which point some thermostat assemblies might be on the edge of opening, or the poppit valve retraction, so it is imperative you know your motor. And don't ever trust a Clymer or Seloc manual ...

So for those 2 options ... and that my friends is why the OEM factory, dealers and authorized/certified brand servicers use specific "test wheels or props" for the motor in question.

In-Water Test - THE best choice IF/when diagnosing anything IMHO ... (Note a test wheel can be used for tests where specified in the OEM service manual.)

 

[onthewater102]

Good luck finding a test wheel kit though for less than half the replacement cost of your motor. I wanted one to check & adjust my timing advance, ended up with the boat on a trailer at the launch trying to figure it out which is not right but was the best I could do.

I agree w/ Dale, muffs are good for running the motor in the backyard to fog it before you put it away for the winter, barrel is only marginally more useful for specific issues.

 

[nccatfisher]

Like has been said, you can't get any load test in a barrel or muffs. I do a half way load test on mine by backing the boat on the trailer in my pond and leaving the trailer hooked to my UTV. That isn't a perfect world but you can get a better idea what it is doing.

 

[Weldorthemagnificent]

If you get a barrel, you can always throw yer laundry in and kill two birds with one stone....just saying. Muffs won't clean yer socks!


Sent from my iPhone using Tapatalk

 

[LionHeart]

Thanks for all the info guys. I think I'll just be using the muffs for idle check and fwd/rev check at idle.

 

[DaleH]

Good luck finding a test wheel kit though for less than half the replacement cost of your motor.

Oh, I am aware of that for sure! I wasn't advocating 'buying one', just tried to point out that there's a valid reason 'why' the exist, that's all.

In my case, over the years my bros and I had so many OBs and referred so many people to a local shop that they'd let me borrow any of the OEM tools I needed ...

 

[turbotodd]

I use a horse trough. It works quite well for portables all the way up to the 150's that we seldom see.

with portable outboards in a horse trough, you can put it in gear and actually load it a little. You put a 150 in gear-even at idle-and it will empty most of the water in a few seconds.

Muffs. Bad part about muffs is that the water hose is pressurizing the cooling system, so you have no idea how well, or IF, the water pump is functioning. The water hose is just forcing water right through the pump and up into the engine, then out the pee hole. This is exactly why I switched from muffs to a 100 gallon stock trough. It does a better job of duplicating actual lake conditions. It's just big enough to be able to put portables in gear and load them, but not so big that it's in the way all the time. I also use it for checking tires for leaks, so it has multiple purposes around my shop. It works really well but you still can't totally duplicate actual running conditions. But at least you'll know that it will start and run before you get to the lake/river/pond.

Another poster mentioned a test wheel. I bought one a while back that fits the Yamaha 25's since I seem to do a bunch of them, and it was almost $300 retail; and while it is useful, it isn't worth the money, not in a 100 gal tank. It still makes a mess just not quite as fast as a regular prop does. It's purpose is to be able to test the motor without having to actually drive the boat, meant to be used at a dock or marina, or a ramp for that matter.

RPM on muffs? You can go wide open if you want, not for very long obviously, and there is very little load on the engine. If it comes apart after running for 2 seconds at no load, it was going to come apart while in the water under normal loading; and it's as simple as that.

 

[stinkfoot]

How about a jet? My 40 hp jet dumps the contents of a 50 gal barrel all over me in about 3 seconds...

 

[turbotodd]

How about a jet? My 40 hp jet dumps the contents of a 50 gal barrel all over me in about 3 seconds...

In a horse tank, a jet (usually 40/30) will work good in "neutral". Once placed into "forward", at full throttle, it will dump 50 gal of water in about 2 seconds. I like to tilt it up and wash the cars next door at the dealership, about 100 feet away from the motor. There's been times I've been on the water fishing when another boat gets too close and I wish I had a jet foot for that one reason.

At idle, it still dumps some water out, but obviously not quite as fast. Get about a minute in forward gear-at idle only (800 RPM).