Search found 23 matches

by alfaguy
24 Oct 2015, 07:57
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

Does anyone change the plastic timing cam when making the 25 to 30 conversion. Another post indicated they are different, even though the parts breakdowns show the same number for both models. I ordered the part quoted and they are indeed different, and it seems the 30 hp cam does not advance as qui...
by alfaguy
18 Nov 2014, 08:29
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

I think it needs fuel during the transition from low to high speed. I will flush the transfer holes again to see if something got in there after I rebuilt the carb. The main jet is 0.067 so it should be getting plenty of fuel at high speed. I am having trouble with the Faria tach above 3500 rpm so I...
by alfaguy
18 Nov 2014, 08:23
Forum: Motors
Topic: Misfire at specific RPM with bigger carb
Replies: 2
Views: 1039

Misfire at specific RPM with bigger carb

Thanks for the response Pappy. I suspect it is the transfer point but did not explore timing yet. It is set with the roller between the marks when the butterfly starts to open, but I will play around with it. My testing will be done in the water. A #53 drill fits the main jet, so it should be 0.067 ...
by alfaguy
16 Nov 2014, 09:31
Forum: Motors
Topic: Misfire at specific RPM with bigger carb
Replies: 2
Views: 1039

Misfire at specific RPM with bigger carb

After fitting a larger carb, I took my Evinrude 25/30 to the river and it ran really well except for a severe misfire at 2200 rpm. It is fine at 2000 and 2500 but totally breaks up at 2200. I installed a new power pack, coils and plugs (but not wires) two years ago. The "new" carb is a choke type pr...
by alfaguy
11 Nov 2014, 19:12
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

Took my 25/30 to the river and it ran really well except for a severe misfire at 2200 rpm. It is fine at 2000 and 2500 but totally breaks up at 2200. It has a new power pack, coils and plugs (but not wires). Any suggestions on how to cure it. Also I could not get above 4500 rpm with a 10-13 prop. I ...
by alfaguy
07 Nov 2014, 08:49
Forum: Boat House
Topic: Adjustable Jack Plate
Replies: 20
Views: 3929

Adjustable Jack Plate

Here are photos of the adjustor from today. The middle photo shows how I captured the bottom nut, so it could move a little to self align itself. The jackplate is bolted together without any welding.
by alfaguy
07 Nov 2014, 08:10
Forum: Boat House
Topic: Adjustable Jack Plate
Replies: 20
Views: 3929

Adjustable Jack Plate

I made the slots as you did, by drilling a series of holes and sawing and filing between them. I was careful to locate the hole centers and center punched the locations so they would be precisely drilled. A couple new files helped cut quickly. You can make your unit adjustable like mine by installin...
by alfaguy
06 Nov 2014, 08:38
Forum: Boat House
Topic: Adjustable Jack Plate
Replies: 20
Views: 3929

Adjustable Jack Plate

I am revisiting my old post and can't believe it started 3 years ago. The jack plate is working great and I would not have done anything differently other than using all stainless steel fasteners. I have a couple regular cadmium plated bolts and they are showing some oxidation now. Having the jackpl...
by alfaguy
06 Nov 2014, 08:24
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

I installed my 30/35 hp choke type carb on my 25 and she cranked right up. I was surprised to find my intake manifold has the larger hole to match the bigger carb, so the manifold I bought is not needed. I am headed to the river tomorrow for a long weekend of hunting and fishing. A great test and fi...
by alfaguy
02 Nov 2014, 10:19
Forum: Motors
Topic: Home made riser questions
Replies: 13
Views: 1884

Home made riser questions

I started a post a few years ago on the jackplate i made.

See if this works for you.

https://forum.tinboats.net/viewtopic.php?f=3&t=22597
by alfaguy
23 Oct 2014, 08:23
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

I received a suggestion to drill my early carb on another post and press in the primer nozzle tube. This sounds like a good idea if I can do it successfully. Has anyone else tried this??
by alfaguy
23 Oct 2014, 08:20
Forum: Motors
Topic: Johnson 20hp primer vs choke
Replies: 7
Views: 579

Johnson 20hp primer vs choke

I may try the drill and transfer trick. Has anyone else done this?
by alfaguy
20 Oct 2014, 12:23
Forum: Motors
Topic: 1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics
Replies: 185
Views: 55935

1980's Johnson/Evinrude 20/25hp conversion to 30hp with pics

I am upgrading my 1988 25hp to 30 and bought an early carb with a choke plate. I am wondering if I can make a hybrid carb with the bottom from the 25 and top from the 30? I would have to insert a primer fitting in the old carb behind the throttle plate. Probably safer to use the choke system. Dave
by alfaguy
20 Oct 2014, 11:32
Forum: Motors
Topic: Johnson 20hp primer vs choke
Replies: 7
Views: 579

Johnson 20hp primer vs choke

You could get a choke carb from a pre 84 model and make a Frankenstein carb with parts from both.
by alfaguy
12 Feb 2012, 10:55
Forum: Wanted
Topic: 1950's Fast Twin Wanted
Replies: 6
Views: 773

1950's Fast Twin Wanted

I am looking for a running 18 hp Evinrude/Johnson motor from the late 50's for a classic boat project. I need the engine with the vertical split cowl. I live in Tallahassee, FL but often travel south. Any leads on collectors in the south who may have an extra engine would be appreciated. Dave Anders...