No Muffy...No Start

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guywithboat

Petty Officer 2nd Class
Joined
Mar 19, 2006
Messages
101
Hi All,

My 1967 Johnson 4 cylinder, 65 hp, model VXL-13A runs fine in the back yard on a muffy. When I get it in the lake it doesn't want to start.

Can someone assist me or do I need to add wheels and a driveline?;) Thanks for your attention.

Pete
 
W

Walker

Captain
Joined
Jun 15, 2002
Messages
3,085
Re: No Muffy...No Start

Do a compression test. You have no exhaust backpressure running on muffs.
 
jimmbo

jimmbo

Supreme Mariner
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May 24, 2004
Messages
12,967
Re: No Muffy...No Start

the model # given is for a 67 60hp
 
V

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
Re: No Muffy...No Start


compression tester 24.00 at auto zone i dont have one but that backpressure was what i was thinking to we will see jrr
 
A

AlanR

Petty Officer 1st Class
Joined
Jul 14, 2006
Messages
310
Re: No Muffy...No Start

Sounds low on compression... Yeh check it out.
 
D

dsinger

Chief Petty Officer
Joined
Aug 6, 2004
Messages
424
Re: No Muffy...No Start

How did you check your spark just off the plug or space the jump.
 
G

guywithboat

Petty Officer 2nd Class
Joined
Mar 19, 2006
Messages
101
Re: No Muffy...No Start

Assuming it has low compression, other than rebuilding the engine, are there any other fixes?

J, I thought you said you already tested the compression...

It has a new coil, the spark was tested the backyard way. I will need to get a spark tester.
 
R

rwise

Captain
Joined
Jul 5, 2001
Messages
3,205
Re: No Muffy...No Start

seafoam can restore compression if the cause is carbon.
 
G

guywithboat

Petty Officer 2nd Class
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Mar 19, 2006
Messages
101
Re: No Muffy...No Start

rwise,

I am new to boats, what is seafoam? Thank you all for your help.
 
R

rwise

Captain
Joined
Jul 5, 2001
Messages
3,205
Re: No Muffy...No Start

you can get it at auto zone or other parts houses $5 - $8 per can, could be well worth it if it restores the compression
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,762
Re: No Muffy...No Start

SeaFoam "may" restore compression if its due to sticking rings and carbon build up. If the engine is simply worn out, SeaFoam has no restorative capability.
 
D

dsinger

Chief Petty Officer
Joined
Aug 6, 2004
Messages
424
Re: No Muffy...No Start

What makes everyone think this is a compression problem.
 
V

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
Re: No Muffy...No Start

PETE I DID CHECK THE COMPRESSION ON IT ABOUT
2 YEARS AGO AND THEY WERE ALL WITHIN 4 OR FIVE % OF EACH OTHER THEN HOWEVER I DID IT BY MYSELF AND IT WAS MY CHERRY POPPER

I HAVE HEARD MIRACLE STORIES ABOUT SEAFOAM
 
V

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
Re: No Muffy...No Start

Think about it. Some folks dole around at trolling speeds or non-planing speeds for hours. That leads to serious deposit build up. Add oil in the fuel and you get the problem described.

PETE WHILE READING THE SEAFOAM INSTRUCTIONS

I SAW THIS AND THIS CAME TO MIND

I HAD THAT MOTOR FOR TEN YEARS
AND THAT IS THE ONLY WAY I REALLY RAN IT
I HAD IT AT WOT ONCE

I WOULD SAY THIS WOULD BE OUR NEXT STEP
SEAFOAM WWYD
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: No Muffy...No Start

always test compresion and spark at the start of any 2 stroke trouble shooting session, just because it was ok this morning may be meaningless this afternoon. then go look in the exhaust relief tube for insect nests. had an old 105 chysler do just what you describe and it was a dauber nest. had a new pair of 90 tohatsu´s do it as well and had to drill out the relief into the ex tube to make it idle in the water. only thing different from the muffs to the lake is back pressure on the exhaust.
 
V

VADER8674

Petty Officer 2nd Class
Joined
Mar 20, 2006
Messages
107
Re: No Muffy...No Start

compresion check done

warmed engine up to temp

and ran the test 3 times

cyl 1 2 3
#
1 50 45 45
2 80 80 79
3 80 80 80
4 80 80 80

the plugs were dark black with visible chunks

the engine has been ran alot at 1/4 throttle i think we"ll try the seafoam any other ideas checked for dirt dobber found some build up around heads but none in the exhaust .

again engine idles well and and throttles up well on muffs

spark is 3/8 of an inch with spark tester with new coil

ideas thanks in advance
 
jimmbo

jimmbo

Supreme Mariner
Joined
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Messages
12,967
Re: No Muffy...No Start

If your compression gauge is accurate those numbers look low. Even if the gauge is reading lower than the compression really is you still have one cylinder that is too low.
 
G

guywithboat

Petty Officer 2nd Class
Joined
Mar 19, 2006
Messages
101
Re: No Muffy...No Start

Off to get seafoam, I hope to post the results this evening or in the morning.
 
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