9.5 evinrude has spark and gas, won't start

[gtorr]

1972 9.5 evinrude with almost new powerhead. After putting new powerhead in old motor, it started 1st or 2nd pull and ran perfect for several months until a week ago. Then it stopped after starting and won't restart. Still has fair spark of about 1/8" on both plugs and gas getting to carb. Tried squirting gas in throat of carb and in cylinders. Nothing happened. I removed flywheel and checked woodruff key, points setting and coils and all looked okay. Took off carb, soaked in carb cleaner, blew out with compressed air and reassembled. Still dead as a doornail. Possible that the synch/timing is off but hardto tell.

Can't figure out what is wrong. Any ideas and suggestions appreciated.

 

[TrueNorthist]

Re: 9.5 evinrude has spark and gas, won't start

How is the compression?

 

[Tim Frank]

Re: 9.5 evinrude has spark and gas, won't start

Compression?
Might have needed to re torque head bolts after a few hours.
If compression is really low, try a new gasket.

 

[nwcove]

Re: 9.5 evinrude has spark and gas, won't start

as mentioned, check compression. also CLEAN the points. ( the slightest amount of oily residue , even from running in a barrel , will make what you think is "fair spark"....but it wont light the wick, so to speak.)

 

[boobie]

Re: 9.5 evinrude has spark and gas, won't start

The spark should jump a 1/4 " open air gap on a spark tester.

 

[TrueNorthist]

Re: 9.5 evinrude has spark and gas, won't start

Get yourself one of these. Doesn't have to be from those guys. Local parts store will have em.

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

Thanks for the suggestions. It never occurred to me to test the compression since it is a new powerhead with probably less than 5 hours on it. I just tested it now with a screw-in tester and to my surprise, there was just 70 psi on the top cylinder and 120 on the bottom. I also used a spark tester and found that the spark would jump a 3/16 gap, but it wouldn't jump 1/4".

Does the compression difference suggest a blown head gasket? Do you think the spark is lively enough to work if I fix this, or will I need new coils too. Didnt see any cracks on the coils or sign of deterioration but they have been sitting for 40+ years in the powerhead carton.

 

[Tim Frank]

Re: 9.5 evinrude has spark and gas, won't start

Head gasket would be my 1st guess....and the head will have to come off in any case.
Do you know when the impeller was last changed? It might be deteriorating and motor might be running on the warm side.

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

A new impeller was put in at same time as powerhead was changed - should be good.

 

[RogersJetboat454]

Re: 9.5 evinrude has spark and gas, won't start

Does the discrepancy in spark coincide with the cylinder that has low compression, or do you have weak spark on both cylinders?

If you have weak spark on just the cylinder with low compression, I would address the spark issue first, get the engine running, then re-check the compression on the weaker cylinder.

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

The spark seems to be the same on both - weak but can jump 3/16". Also it managed to fire both cylinders for a month before motor stopped... I will take off the head and see what the gasket and top cylinder looks like next.. thanks

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

Well, I just took off the cylinder head and am still mystified. The bottom cylinder had a puddle of liquid gas in it -no water in it that I could see. Gas was probably from me squirting gas in both cylinders earlier. The top cylinder was normal -light oily cover, no loose gas. No sign of any damage to head gasket. No signs of scoring or overheating in either cylinder, and pistons looked normal and moved easily.

Is it possible that I "permanently flooded" it by squirting gas in eariler?. Why none in top cylinder? Would gas in it be enough to raise compression by 50 psi in lower cylinder? Would it stop it from firing?

What should my next step be?

 

[Tim Frank]

Re: 9.5 evinrude has spark and gas, won't start

Well, I just took off the cylinder head and am still mystified. The bottom cylinder had a puddle of liquid gas in it -no water in it that I could see. Gas was probably from me squirting gas in both cylinders earlier. The top cylinder was normal -light oily cover, no loose gas. No sign of any damage to head gasket. No signs of scoring or overheating in either cylinder, and pistons looked normal and moved easily.

Is it possible that I "permanently flooded" it by squirting gas in eariler?. Why none in top cylinder? Would gas in it be enough to raise compression by 50 psi in lower cylinder? Would it stop it from firing?

What should my next step be?

I've seen so many odd things with a shot head gasket....including stuff that can't really be explained, that if you have a new head gasket in hand, I'd suggest throwing it on and see what you get.
If that does get you up and running, make sure that you re-torque your head bolts at the suggested interval.

 

[belairbrian]

Re: 9.5 evinrude has spark and gas, won't start

My 48 SPL recently stopped firing on one cylinder (lower). Compression was equal on both cylinders. Both had good spark and were getting fuel. In fact too much fuel. Carbs were rebuilt and all is better now. Apparently some trash got in there and was causing it to flood out.

The shop also replaced the fuel lines and added an inline fuel filter.

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

I put the head back on after drying out the gas in the cylinder. (Didnt have a new gasket to hand so re-used old one as temporary measure.) Pulled choke out and tried it. It actually gave a cough but then stopped right away. First sign of life in a week! I alternated three pulls with choke on and 3 with choke off for 15 min but no action. Smelled flooded again. Will try to understand synch/timing and reset this before buying a carb kit or (shudder) new coils @ $30 each. Also was wondering if reeds ever get stuck or damaged?

 

[Tim Frank]

Re: 9.5 evinrude has spark and gas, won't start

Try the compression test now, with the old gasket.

 

[gtorr]

Re: 9.5 evinrude has spark and gas, won't start

Good suggestion, Tim. Tried this and got 70 psi on the nose for both cylinders this time. Bottom cylinder already looked like it was getting too much gas, with some visible in plug hole. Thanks

 

[nwcove]

Re: 9.5 evinrude has spark and gas, won't start

have you tried taking the fuel pump out of the mix and gravity feeding it fuel?

 

[Rick.]

Re: 9.5 evinrude has spark and gas, won't start

Thanks for the suggestions. It never occurred to me to test the compression since it is a new powerhead with probably less than 5 hours on it. I just tested it now with a screw-in tester and to my surprise, there was just 70 psi on the top cylinder and 120 on the bottom. I also used a spark tester and found that the spark would jump a 3/16 gap, but it wouldn't jump 1/4".

Does the compression difference suggest a blown head gasket? Do you think the spark is lively enough to work if I fix this, or will I need new coils too. Didnt see any cracks on the coils or sign of deterioration but they have been sitting for 40+ years in the powerhead carton.

The problem is the 120 not the 70 reading. 70 is very normal for that motor but never heard of anyone pulling 120 on a 9.5 before. Best of luck. Rick.

 

[TrueNorthist]

Re: 9.5 evinrude has spark and gas, won't start

Are the plugs wet after pulling for a while? Also, you will get a high reading if there is a badly flooded cylinder. I am beginning to wonder if you aren't just flooding it while starting? You should never choke it again after it "coughs". Those things are terrible for flooding.