Moderated Discussion Areas
  ContinuousWave: Whaler Performance
  Engine Flush - To Muff or Not to Muff

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Engine Flush - To Muff or Not to Muff
huladick posted 09-05-2002 07:59 PM ET (US)   Profile for huladick   Send Email to huladick  
My 2000 Johnson 35 has the outlet for direct connection for the hose when flushing. Do I need to run this way or should I go back to the muffs and run it ?
jimh posted 09-05-2002 08:31 PM ET (US)     Profile for jimh  Send Email to jimh     
I would take the advice of the owner's manual. What does the manual say on this topic?
Swellmonster posted 09-06-2002 09:59 AM ET (US)     Profile for Swellmonster  Send Email to Swellmonster     
My guess would be use the direct hose attatchment and DO NOT start your motor. It flushes this way.
huladick posted 09-08-2002 08:58 PM ET (US)     Profile for huladick  Send Email to huladick     
The owners manual gives procedures for both running and not with the hose adapter. Just wondering if it gets past the thermostat with the motor not running. Thanks.
FISHNFF posted 09-09-2002 12:38 AM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
My question exactly.
My Merc manual stated run motor at idle. My friends Suzuki manual states, if I remember right, "Do not run engine."


FISHNFF posted 09-09-2002 12:42 AM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
Because my boat spends part of its life berthed in the salt, I use the flushing attachment with the motor tilted clear of the water, so as not to ingest any water through the lower unit water intake ports, with no fuel delivery problems. I thought the fuel would not flow right. So far, OK


Jay A posted 09-09-2002 12:47 AM ET (US)     Profile for Jay A    
Better yet,get a big enough barrel to lower the engine into. fill it with water with the garden hose running to keep it fresh. start the motor and disconnect the fuel line at the tank and let it run out of gas. This will also "muffle" the the engine keeping the neighbors happy. I've been doing this to my 40hp Merc since it was new in 1975! It's still going strong with (knock on wood) no repairs!
BQUICK posted 09-09-2002 04:36 PM ET (US)     Profile for BQUICK  Send Email to BQUICK     
I was wondering 1980 Merc 90 manual says NOT to run it when flushing with muffs.
I have always started and idled. I guess it's not necessay to run??


Bigshot posted 09-10-2002 09:52 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Hold up here.....with muffs you have to run it. Do you have water coming out the indicator with it So there fore no water ever reached the powerhead.

With the factory flusher on the stern of the engine, you do NOT run the engine. This is basically a backflusher and running the engine(although it may not ruin the impeller or effect the engine)will fight the flow of water.

BQUICK posted 09-12-2002 03:03 PM ET (US)     Profile for BQUICK  Send Email to BQUICK     
....maybe Merc stated that so the motors wouldn't last as long. Ya never know....
I had to read it a couple times to believe it.
I would think to get past the impeller it would have to be running.

....geez just realized my initials are the same as Boston Whaler

BQUICK posted 09-12-2002 03:05 PM ET (US)     Profile for BQUICK  Send Email to BQUICK     
Hey had a thought.....Could I make a backflusher by running water in thru the telltale?? I'd rather not run the motor if I don't have to.
Al_A_Buy posted 09-12-2002 04:59 PM ET (US)     Profile for Al_A_Buy  Send Email to Al_A_Buy     
Bquick - I wouldn't think that you would get much flow through the telltale.

Huladick - check the brand of flushing unit. If it is the same one available at most marine centers, it has a pulse function that helps prevent / loosen deposits in the water jacket, preventing corrosives build up.

diveorfish posted 09-12-2002 06:39 PM ET (US)     Profile for diveorfish  Send Email to diveorfish     
This is what my dealer told me:
If you trailer the boat, use the muffs. Even though the engine has the outlet for direct connection, it is best not to mess with it because certain undesirable outcomes may occur: 1. You might loose the plug or forget to put it back in. 2. You may not tighten up the plug enough. 3. You may over tighten and strip the threads on either the plug or the engine itself. Although these outcomes are probably very unlikely, Murphy’s Law sometimes catches up with you. By contrast, the muffs are pretty much fool proof.

If you slip your boat though, do you even have a choice? It would seem to be very difficult to get close enough to slip on the muffs. I imagine that would make the outlet direct connection method the only alternative.

huladick posted 09-15-2002 07:38 AM ET (US)     Profile for huladick  Send Email to huladick     
Lots of good comments and suggestions. I have always used the muffs in the past, but now I have the built-in flush adapter. I have only ised the adapter up to this point, but still don't feel like it get in the power head when "back-flushing". Guess I'll go get another pair of muffs. Thanks for all the ideas..... Dick M.
Bigshot posted 09-16-2002 11:16 AM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Rmember that if muffs slip roast the engine or waterpump. Backflushing is safer, plugs won't foul, neighbors don't care, etc. manufacturers did not install them for nothing.
Steve Leone posted 03-28-2004 12:29 PM ET (US)     Profile for Steve Leone  Send Email to Steve Leone     
Try my OUTBOARD MOTOR BACKFLUSHING device !!! You can buy it on Ebay. IT REALLY WORKS !!! Over 4000 satified customers so far !!! Steve Leone 510-528-1516
Legobusier posted 03-28-2004 06:52 PM ET (US)     Profile for Legobusier  Send Email to Legobusier     
I was wondering the exact same question yesterday as I hooked my muffs up to my Honda 90. I just bought the boat (used) and have never used the hose attachement. My thinking on this is pretty simple...flush it the same way you cool it and in the same direction....fresh water in/salt water out. I guess the hose connection would work fine, but it seems like the lower ports might not get a good flush. I'll have to try it some time.
Chuck Tribolet posted 03-29-2004 12:36 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
I've used the hose hookup on my Evinrude two stroke 90 just
about from new. I do carry a spare plug for it, and I make a
point of putting the plug IN the boat so if I forget to put it
back, it stays. Finger tight is fine. I don't run it on
the hose (owner's manual says you don't have to) because it's
quiet noisy.

A buddy's Merc 90 four-stroke has no plug. You screw the hose
over the telltale, and there's a check valve behind the
telltale that lets the water flow in. Pretty slick. And
really quiet when he runs it on the hose.


tarbaby posted 03-29-2004 07:59 AM ET (US)     Profile for tarbaby  Send Email to tarbaby     
I flush with the hose attachment on my Johnson. I was in the middle of Beaufort Inlet and my overheat alarm went off. I looked back and there was no stream through the telltale. The plug had come out and with out it there is not enough back pressure to cool the engine. The water coming out was a trickle and real hot.I carry a spare just for this reason. I put the spare in and restarted the engine. The water was hot at first and then cooled to the touch. This happened all in a matter of about a minute. Nice to know that all of the systems work the way they were designed. I was able to get out and fish but I did get skunked that day......

All that said, I still flush with the hose attachment. I just tighten it better now.

elaelap posted 04-21-2004 06:41 PM ET (US)     Profile for elaelap  Send Email to elaelap     
My Yamaha four stroke has a hose attachment for flushing; no 'plug' to lose, but I guess it might be easy to leave it unattached after flushing...I've been lucky so far. The dealer and the manual said NOT to turn on the motor while flushing this way...said you could burn out something in the bottom unit. I've used only this method of flushing since I bought the motor new one year/370 hours ago...simple, quiet, no complaints, and the motor runs like a top. Some of the old hands at the ramp have warned me against this method, and I really don't know whether it's as effective as flushing with earmuffs, but that's why there are warranties. By the way, 95% of my motor's use is in salt water, and I flush immediately after each use.


north end boston posted 04-23-2004 11:53 AM ET (US)     Profile for north end boston  Send Email to north end boston     
Anywhere on-line I can read instructions for flushing Yamaha 40hp 4 stroke? use it all saltwater boston harbor.

It does have this attachment elaelap speaks of?

first boat, no manual with motor - out of luck, but i want to flush and keep motor running properly. many thanks for info.


NausetBoy posted 04-23-2004 04:23 PM ET (US)     Profile for NausetBoy  Send Email to NausetBoy     
Alright. I have been here before. You can flush it with the direct connection, but you need to do it when the engine is warm. That way the thermostats are open. If it is cold you are missing part of the engine.
RAGE23 posted 04-24-2004 08:49 AM ET (US)     Profile for RAGE23  Send Email to RAGE23     
I HAVE TWIN 2000 135 OPTIS.. JUST WONDERING IF IT IS OK TO LEAVE THE QUICK CONNECT FITTINGS IN? sould engine be up or down? there is a separate fitting in back for flushing
FISHNFF posted 04-24-2004 11:40 PM ET (US)     Profile for FISHNFF  Send Email to FISHNFF     
Interesting note. Here in San Francisco, there is an restaurant on a floating island, called "Forbes Island." They have a shuttle boat to and from Pier 39 with twin Yamaha 50 4 strokes. They keep water running through the flushing hose 24/7. The motors are tilted and a stream of water 8' is going everytime I stop by. A little overkill and a lot of waste!


P.S. Just a note. I just purchased a Tohatsu 9.8 4 stroke, and the flushing instructions are to use the supplied attachment, which connects to a garden hose. Next TAPE the water intakes, turn on water, then start motor. REMEMBER to remove tape when done! Good thing is it only weighs 81 lbs. Bah is that they cut out the iol filter.

Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.