It is currently 16 Nov 2018, 03:37
Join the free forum or login with your account and the annoying banner goes away

mud-skipper

All times are UTC - 5 hours [ DST ]




 Page 1 of 1 [ 12 posts ] 
Author Message
 Post subject: 1977 40 hp Merc 402
PostPosted: 17 Oct 2016, 21:07 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
Maybe somebody can help me out with my problem. Motor looks almost brand new but wiring was corroded when I bought it. Replaced wiring and rebuilt carb and fuel pump. Motor still surges. Swapped carb(have a parts motor) Still surges. It's a jet. Any bright ideas?


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 18 Oct 2016, 10:54 

Joined: 19 Jan 2012, 07:44
Posts: 2926
Location: Northeast Arkansas
stinkfoot wrote:
Maybe somebody can help me out with my problem. Motor looks almost brand new but wiring was corroded when I bought it. Replaced wiring and rebuilt carb and fuel pump. Motor still surges. Swapped carb(have a parts motor) Still surges. It's a jet. Any bright ideas?

Surging does sound fuel related, but a jet wouldn't be my first suspect. I'd look for air leaks in the fuel system first. If that didn't solve the problem, then I might start going through the entire fuel system.



_________________
Mike
My boat mod viewtopic.php?f=21&t=23359
Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 18 Oct 2016, 16:05 
Donor
User avatar

Joined: 02 Mar 2014, 19:52
Posts: 3193
Location: Central FLORIDA - The Sunshine State -
Like Mike said: go through the entire fuel delivery system

it only takes a small issue to cause fuel starvation.
I would go to the squeeze bulb, check for any air leaks. If it is hard and brittle, replace it.
then, all the hose clamps and fittings.
work from the gas tank to the fuel pump then to the carb.

good luck = this is one of the most aggravating conditions in the outboard.



_________________
http://www.tinboats.net/how-to-build-a-transom/
http://www.tinboats.net/varnish-vs-polyurethane/
All about Primers = http://www.tinboats.net/primer-and-paint-basics/
Paint, Thinners and Applications = http://www.paintingforpainters.com/

1959 Crestliner Commodore 14'
1959 Lone Star Malibu 14'
1958 Johnson 35 RDE-19 Sea Horse
1958 Johnson 35 RDS-20 Super Sea Horse
Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 18 Oct 2016, 19:55 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
Tell me about it! Thanks guys, will try that.

Not the tank, hose or bulb as my 20hp Merc prop runs perfectly fine off it. I have also removed all zap straps from the fuel lines and replaced with hose clips to no avail.


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 01 Nov 2016, 18:23 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
Tore the fuel pump assembly apart today to discover a half inch tear in the diaphragm. Pick up new diaphragm and gaskets tomorrow. Hopefully that's it.


Offline
 Profile  
 
 Post subject: Re: 1977 40 hp Merc 402
PostPosted: 03 Nov 2016, 06:34 
User avatar

Joined: 08 Jul 2015, 08:37
Posts: 97
Location: Greenfield, Indiana
I would say the fuel pump is sucking air or clogged. I had the same problem you described with my 1973 Johnson 25 HP. Which is funny because when I bought the motor the guy told me he had all the fuel system replaced. The torn gasket is probably your problem.

Sent from my XT1254 using Tapatalk


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 27 Jan 2017, 02:26 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
32418810331_d4e21f686f_o.jpg
Finally fixed this POS! Hallelujah! Could not have done it without a parts motor....


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 21 May 2017, 20:44 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
OK, next problem. Had some family over to visit from the UK. Took the g/fs son and mine for a trip up river. The motor has become progressively harder and harder to start although it eventually usually does. A friend who is a mechanic told me that was probably reed valves.This trip however, after starting two or three times it gave up. Starter was very hot when I removed cover and it wouldn't fire even with a rope. Starter sounded like a flat battery but it was a brand new fully charged starting battery leading me to think it was somehow jamming or seizing. We got back to the launch(thankfully about 8km downstream) on electric motor power only(took us 3 hours) proving that the battery wasn't flat even though the starter was choking like it was. Any ideas? On the plus side here's where we broke down.....
20170520_145842.jpg
20170520_143643-EFFECTS.jpg


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 22 May 2017, 12:10 

Joined: 04 Feb 2013, 22:11
Posts: 424
You didn't say how it felt when you tried it with the rope? Did it pull normal for a motor that size, feel stiff like it was trying to seize gall up? Need more info. Could be numerous things.

With it having hard starting issues prior to this I would hope it isn't catastrophic like a galled or seized piston, and more like a fuel delivery or reed issue.

When you say it has been progressively hard to start was it spinning over normally as in fast but just not firing, or was it spinning over slow like a dragging starter?


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 22 May 2017, 17:04 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
nccatfisher wrote:
You didn't say how it felt when you tried it with the rope? Did it pull normal for a motor that size, feel stiff like it was trying to seize gall up? Need more info. Could be numerous things.

With it having hard starting issues prior to this I would hope it isn't catastrophic like a galled or seized piston, and more like a fuel delivery or reed issue.

When you say it has been progressively hard to start was it spinning over normally as in fast but just not firing, or was it spinning over slow like a dragging starter?

Slow like a flat battery but the battery obviously not flat as it got us home with the EMO. Felt normal when pulled with rope and I have started with rope before after I flattened trolling motor battery. Previously there was lots of turning over but little firing. Now turning over very sluggishly. Starter motor felt very hot. Have to admit I haven't looked at it since. May swap starter with my parts motor and perhaps coils too. Hard to run a jet in a barrel without wearing the contents of the barrel in about 3 seconds flat!


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 22 May 2017, 20:57 

Joined: 04 Feb 2013, 22:11
Posts: 424
stinkfoot wrote:
nccatfisher wrote:
You didn't say how it felt when you tried it with the rope? Did it pull normal for a motor that size, feel stiff like it was trying to seize gall up? Need more info. Could be numerous things.

With it having hard starting issues prior to this I would hope it isn't catastrophic like a galled or seized piston, and more like a fuel delivery or reed issue.

When you say it has been progressively hard to start was it spinning over normally as in fast but just not firing, or was it spinning over slow like a dragging starter?

Slow like a flat battery but the battery obviously not flat as it got us home with the EMO. Felt normal when pulled with rope and I have started with rope before after I flattened trolling motor battery. Previously there was lots of turning over but little firing. Now turning over very sluggishly. Starter motor felt very hot. Have to admit I haven't looked at it since. May swap starter with my parts motor and perhaps coils too. Hard to run a jet in a barrel without wearing the contents of the barrel in about 3 seconds flat!
Since you have changed the wiring I would hope you don't have a loose connection on the starter or solenoid, that is always the first place to look. Then of course you check battery leads/connections. If all that checks out your starter is naturally suspect, worn brushes usually will make it not do anything at all and with a bump then start right up. High heat is a sign of a poor connection/low voltage or shorted windings.

If all your wiring/connections check out and you are getting full voltage through your solenoid (which you can bypass for a test easily) then it is time to have your starter load tested or if you have a known good one on your donor motor switch them.


Offline
 Profile  
 
 Post subject: 1977 40 hp Merc 402
PostPosted: 23 May 2017, 01:23 
User avatar

Joined: 05 Feb 2016, 03:42
Posts: 399
Location: Langley, BC
Thanks. New boat coming so may not get looked at for a while.... :D


Offline
 Profile  
 
Display posts from previous:  Sort by  
 Page 1 of 1 [ 12 posts ] 

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 48 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Join the free forum or login with your account and the annoying banner goes away

AirboatCoatings