backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

[usnretired97]

I just bought a used boat. I started it up with a hose going into a fresh can of gas. I can't run it long as it is out of water and if someone knows how to connect water out of water, let me know.<br /><br />It pop pop pops on number 4. I remove number 4 wire and it stops for a minute or so then returns, I put the wire back on and it goes away for a few seconds. Otherwise it ramps up and down fine and yes the pop speed corresponds to the RPM. Again, I only run it for a very short time and keep an eye on the temp.<br /><br />First, I need to verify the timing. It is currently set to 1342. I have a new (looking) distributor cap and points. <br /><br />I changed the wires, I changed the plugs all carbon blacked well, no buildup. I pumped out the oil, it had water in it, but had recently had the head gasket changed. I drained and put new rear end oil in it.<br /><br />I started it back up and it did exactly the same thing. I am at a loss. I don't have a timing light or dwell meter or any of that stuff so I will be going to Sears I guess.<br /><br />I have a broken hose on the tilt mechanisam, that goes to the hydraulic shop on Monday. <br /><br />The blower fan doesn't work either. The guages work and the switches are in fair condition. The interior is trashed though and the inside decking is garbage. I replaced the flooring on my previous Glastron so it's just a crappy job of grinding and fiberglassing.<br /><br />If you have ideas, let me know.

 

[Uncle Dave]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

USN Ret.<br /><br />I would not even crank it over without a water hose hooked up. The lower waterpump is made of rubber and needs a supply of water to lube it and also cool it. Probably a half minute or less of engine time and the pump may be toast. <br />Engine temp sensors need water to sense water temp.<br />The block may be close to melt down before the temp gaauge shows any thing.<br />Also the exhaust manifold is water cooled and the exhaust heats up very fast without the cool water.<br /><br />If you have the fireing order wrong it will run very rough or not at all.<br /><br />I can check my manual tomorrow.<br /><br />Also get youself a manual for that model motor and drive. Almost impossible to do anything without the book.<br /><br />And welcome to the forum. <br /><br />Uncle Dave

 

[rbezdon]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

Did I understand you put rear end oil in it?? If you are referring to the outdrive, get it back out and use the recommended oil. The rear end oil will outgas and cause your unit to fail quickly. If you put it in the engine, you need to use the standard recommended oil, usually straight 30W.

 

[Bart Sr.]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

Get yourself a set of muffs before starting again.

 

[Bt Doctur]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

And if you did already have it running without water plan on a new water pump in the lower unit. 15 seconds without water and its toast. the popping may be a bad valve in #4 due to water from a bad riser

 

[lowshovel1]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

another thing--even if the cap- points and roter "LOOK" new you should replace them.I have learned from this forum that is part of anual maintnance in spring.

 

[achris]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

If you ran it for more than a minute without water, start searching this forum for 'how do I replace water pocket cover'. The hot exhaust gases melt and distort the cover. Even if you get everything else sorted, until that cover is replaced you'll have an overheat problem at higher revs. <br /><br />Chris..............

 

[usnretired97]

Re: backfire & firing order mercruiser 140HP 1973 Glastron Bayflite

Geeze I better get a manual ASAP! I used the 80-90W stuff the mechanic at the boat house recommended for the lower unit and the tilt mechanism. I pulled and cleaned the hoses on the exterior of the tilt mechanism. Off to the hydraulic hose place tomorrow. <br /><br />I used a high quality Pennzoil for the engine. I replaced the filter too.<br /><br />Is the manual here, the seloc a good one to have?<br /><br />Thanks for the inputs, <br /><br />USN