NO GET UP AND GO

[D.Crowson]

I have a 63 75hr speedy 4. JOHSON Just bought it and did a tune up. Every thing is set perfect for the timing and the synchronization. The motor start worm or cold on 4 revolotion (right now) But out on the water when you go full throttle it takes awile to build up speed. Once at top speed i'm only going 22 mil.hr. and the motor has a odd sound not a knock ing sound more like a ticking or a wa wa wa wa sound . Just has no power. what should the compreshion be on the cylinders. someone told me the reeds may be bad is this true??? As i had said befoe it starts great quick on the thottel untill there is a load on it then it take awile to build up speed it's pushing a 16-ft glass boat........ any ideas out there I also have a post down below with no reply's about a 77 25 hr johson with ignition problem any reply is better then none. even if it to tell me to by a new motor. All i now is the fish are getting AWAY !!!!!!!!!!!!!

 

[rwise]

Re: NO GET UP AND GO

D. Crowson<br />What is compresion on all cylinders? Mod, ser, etc.<br />Richard<br />Also I have a similar engine, likes gas, have you cleaned/tuned carb? Highspeed jets!

 

[D.Crowson]

Re: NO GET UP AND GO

Thanks for the reply Richard. the mod#E8RLCSS and yes it likes gas. The compression is 90 on one cylinder and 77 to78 on the rest probably low . I havent done anything with the carb. It has two low idle screws and no high speed maybe a carb problem. I had a 57 35hr and it had a high and low idle screws it was very difficult to get dialed in on this 75 it dont have these screws. What do i look for in the carb. I will reply below on my other post. <br />

 

[rwise]

Re: NO GET UP AND GO

D Crowson<br />looks like the compresion is low on two and maybe low on the other. Have you decarboned?<br />Richard

 

[D.Crowson]

Re: NO GET UP AND GO

HI Richard. I haven't decarboned, what i have done is inspected the pistons through the sparkplug holes. The left head had been changed,When i don't now but it is a differant collar. I'm concerned about the noise once she's opened up. lt's hard to describe. The motor idels fine. once it starts going it runs a little rough then smooth out. then the motor has a strange nose. all most as if it was flooding out or loading up. Acts like it's not running on all cylinders. The bottom sparkplugs are wet and the top plugs are allmost dry. I'm just not sure what to look for. can the reed create such a problem or should i be looking at the carb. This is a cool bulletin board so many people and so many problems i wished i could help them all. some where some how i may be able to help. In the mean time i need all to help me THANK YOU.....

 

[crazyray2]

Re: NO GET UP AND GO

I am not an expert on your engine by any means but will give you a few ideas maybe....using an inductive pick-up timing light check the firing on your bottom plugs( ones looking wet with fuel) at speed maybe firing at idle but losing them at higher rpms...next while under way with a buddy at helm look at each carb throat should see mist in throat but not dripping or puddling fuel...... also if you have bad reeds there will be a spray of intake charge as you are running at speed.....finally if these fail remove one plug wire at a time as you are running....but not at speed.....should be able to find the cylinders that are not pulling their wait........attention to the details will pay great dividends for ya....happy boating

 

[JasonJ]

Re: NO GET UP AND GO

Hate to say it, but your compression is too low to get much more out of it than you already are getting. You could decarbon it, but that will lower the compression even more. Usually, 100 pounds is about as low as you want to go, then its rebuild time. 22 miles an hour isn't horribly bad for that low of compression. I have an 85 horse Merc inline six pushing a 17 footer, and the best I have gotten was 31 mph (gps), and it has great compression and is tuned to perfection. You can try adjusting things, and it may help a little, but I personally feel that the compression is low. If you are brave, you could tear her down, inspect the cylinders, surface hone and re-ring, and that will bring the compression up. Only if you are brave....Either way, good luck....

 

[Fouled Plug]

Re: NO GET UP AND GO

Lower compression? Actually, decarbing will raise compression by un-sticking piston rings. It's always worth a shot, and with your compression readings it's worth the attempt. Follow the instructions on the can-o-miracles you buy and recheck the numbers. If they come up, then we'll go from there.

 

[rwise]

Re: NO GET UP AND GO

I agree with Fouled Plug, but I use H2O to decarbon. It's availible everywhere you find boats. Get the engine warm then have some stear that you trust at about 3/4 throtle drip a small amount of water in the carb. I do one carb at a time, not to much you dont want to drown it! Keep doig that untill all you get s steam not smoke! On a moter that has bad carbon buildup it can bring compresion up 10 to 15 lbs! Dad always said you need at least 80lbs to run, he is a shade tree wrench! I seen him do this many times, though it was his car.<br />Richard

 

[JasonJ]

Re: NO GET UP AND GO

I am curious. While I understand the unsticking of the piston rings, isn't the decarbonizing also removing the build-up of carbon from the piston top and head? Does the freeing up of the rings (if they are even stuck) make up for a millimeters worth of material removed from the surfaces? I'll take your word for it, but it seems that at best the rings would get unstuck, raising the compression a bit, and the carbon would be removed, making the combustion chamber slightly larger in volume, lowering compression a bit, with the end result being little difference. I think I'll get some of this stuff and shoot my Merc with it, I know its carboned up. Then I'll know for sure this isn't the "rebuilt engine in a bottle" syndrome. I have decarboned automobile engines with no effect (liquids and scraping), that is why I am skeptical....

 

[Fouled Plug]

Re: NO GET UP AND GO

I think by the time enough carbon had accumulated on your piston top to raise compression, the motor would have already expired. Two stroke rings will stick much more than 4 strokes due to the carbon from the combustion of the oil. Try a can of Power Tune or Seafoam on your Merc, and take before and after readings of the compression. Let us know how it works. I'll bet it'll be the best few bucks you've spent lately!