Engine Sounds Like A Lawnmover
11-19-2003 | 11:43 PM
#1
Thread Starter
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Joined: Jun 2003
Posts: 33
I have been searching in the forum for the answer to this, but not sure I have found it. Not an expert mechanics at all, so bare with me. Recently, when I start the engine in the morning (12A), it sounds like a lawnmover - I don't know how to better describe it. With the choke fully pulled out, it goes to about 1100 rpm. Then, within a minute or so I hear this brop, brop, broop (with a strong gas smell coming from the exhaust up to this point) and then the normal sound of the engine running. By then the rpm goes up to 2-2.5k and everything seems normal after that. It's like if one of the rotors doesn't start right away and then eventually wakes up and joins the party, if you know what I mean. The spark plugs have 5k miles in them, the wires 20k. I drive the car daily, and at least once a day I drive it hard for a couple of mins or more. Any idea as to what causes this and what can I do to remedy it? thanks guys.
11-20-2003 | 11:02 AM
#3
to infinity & beyond, me
Joined: Aug 2001
Posts: 5,124
From: santurce
how long have u had your car and is this in a cold climate? maybe due to age, change in temp one of the seals might be getting stuck till it warms up a bit.
does it start fine in the morning or is it a lil rougher than usual? maybe, the carb has seen better days and its leaking gas and its flooding that rotor, making it hard to start and bad/low compression till that rotor has burned the extra gas.
for know u can check the compression, likeraceer x suggested, also when u get around to getting new plugs, or if you have old ones laying around, perform the atf treatment and it will help clean the carbon build up...
does it start fine in the morning or is it a lil rougher than usual? maybe, the carb has seen better days and its leaking gas and its flooding that rotor, making it hard to start and bad/low compression till that rotor has burned the extra gas.
for know u can check the compression, likeraceer x suggested, also when u get around to getting new plugs, or if you have old ones laying around, perform the atf treatment and it will help clean the carbon build up...
11-20-2003 | 11:37 AM
#4
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Joined: Jun 2003
Posts: 33
I bought the car in March 2002 with 120k miles, and have put 20k miles on it so far. I'm in California, so no cold weather to speak of. Yes, it is a lil rough to start it in the morning. One of my guesses was what you mention about one of the seals getting stuck until it warms up a bit - carbon build-up maybe? what is the atf treatment? I think I'm going to get new spark plugs soon. Even though they only have 5k miles, 1) I have a heavy foot and 2) they are Denso and I want to go back to NGK.
11-20-2003 | 03:54 PM
#5
to infinity & beyond, me
Joined: Aug 2001
Posts: 5,124
From: santurce
its basically to soak the engine in atf(automatica transmission fluid), overnight or longer if possible. turning the engine by hand every so often. atf loosens the carbon and will fould the hell out of your spark plugs. you can either get the atf in the chambers by way or pouring through the carb and turning the engine. or through the trailing spark plug holes.
11-21-2003 | 11:47 PM
#6
Junior Member
Joined: May 2003
Posts: 26
From: plant city/tallahassee, FL
i have the same problem w/ mine. i gave mine up for dead long ago, but i recently let the atf sit in there for a week and started it up tonight. it smoked like hell but it sounded much better. then after a few redline passes down my long driveway (i have no tag for it) it barely smoked at all (it has 178k miles so some is to be expected). but it died again doing the same thing (it wouldnt get better at higher rpm) and now its just back where it was before...could this possibly be massive flooding in one rotor?
11-22-2003 | 12:02 PM
#7
Thread Starter
Member
Joined: Jun 2003
Posts: 33
To add some reality to the situation, here's how the car sounds first thing in the morning, when in "lawnmover" mode:
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...BCNY5v_AcWDF_Z9.
This is how it sounds if started again later in the day:
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...CNY5v_AjP8.CVIe
and this is how it sounds idling after fully warmed up, with a bonus pedal to the metal at the end:
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...CNY5v_AI96PJvyy
Opinions from the experts and veterans welcome.
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...BCNY5v_AcWDF_Z9.
This is how it sounds if started again later in the day:
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...CNY5v_AjP8.CVIe
and this is how it sounds idling after fully warmed up, with a bonus pedal to the metal at the end:
http://us.f2.yahoofs.com/bc/3fbf8543_c242/...CNY5v_AI96PJvyy
Opinions from the experts and veterans welcome.
11-24-2003 | 06:46 AM
#8
Senior Member
Joined: Dec 2002
Posts: 1,788
From: Perth, Western Australia
So have you done the compression test?
You can use MMO instead of ATF too, but I think everyone tends to do the ATF. When you take off your header, you should be able to poke your finger into the exhaust port and feel the rotor. See if you can push in the apex seals.
PS dont accidently start the engine with your finger in the exhaust port
You can use MMO instead of ATF too, but I think everyone tends to do the ATF. When you take off your header, you should be able to poke your finger into the exhaust port and feel the rotor. See if you can push in the apex seals.
PS dont accidently start the engine with your finger in the exhaust port
11-24-2003 | 09:48 PM
#9
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Joined: Jun 2003
Posts: 33
Originally Posted by drifter' date='Nov 24 2003, 03:46 AM
PS dont accidently start the engine with your finger in the exhaust port
No, haven't done a compression test. Neither know how to do it nor do I have the equipment to do it. I read in the Haynes manual that normal compression test equipment won't work on a rotary engine and a Mazda dealer should be used. True?