Time to rebuild the carbs?

[belairbrian]

1989 48SPL (obviously no VRO). I've owned for about a month.

Starts and runs but is running rough.

Replaced NGK plugs with Champions. Replaced spark plug wires, touching them would shock you so i'd say insulation was breaking down.

Starts fairly easy but runs rough at idle on the hose. So I start trouble shooting.

Find removing top plug wire engine dies. Removing lower plug wire has no effect on engine. So time to figure out why.

Lower plug wire is shooting a very strong blue spark, Since the plugs are new I swap them from top to bottom. No change in operation.

Just to be sure I run a compression test both are between 100 and 105 using the procedure in the manual. Note due to not having both cylinders firing I was having trouble getting engine fully warmed up.

Plugs are wet when I remove them for compression test.

Then I start looking and find NO fuel filter. Factory manual says it should be there but it ain't.

So if your still with me after reading all that I come to the conclusion that I need to:

1) rebuild the carbs.
2) install a fuel filter.

Any other suggestions before i order kits and start tearing things apart?

I have the factory manual as a guide any good videos pictorals around I should review?

Have rebuilt carbs on cars before including the ungodly complicated Rochester Quadrajets, but still may have a few questions.

 

[belairbrian]

Re: Time to rebuild the carbs?

Interesting, Iboats doesn't show my engine at all in the carb kit list. When I put 48 for hp and 1989 for year it returns a V6 engine.

other sights show OMC 0396701 or Sierra 18-7222

 

[Daviet]

Re: Time to rebuild the carbs?

1) You have compression and spark to the lower cylinder, does the fuel pump mount to the lower cylinder, if it does and you have a defective diaphram, it could be flooding the cylinder.
2) here is your filter, screen actually. (321675)

EDIT: Thats the same carb kit number I come up with.

http://www.ishopmarine.com/ishop/js...nown&isFrPG=false&forItemCode=&pCode=C0144315

 

[belairbrian]

Re: Time to rebuild the carbs?

So I pulled the lower carb off and found some dirt in the bottom of the bowl. Cleaned it and any passages I could find, reassembled, reinstalled and lower cylinder is now running.

But I noticed some pooling of fuel in the upper. So, off it comes and I find float out of adjustment and 3 pieces of rtv in the fuel bowl. Cleaned that out and reinstalled. Noticed a crack in the upper fuel line so I'll go ahead and replaced the lines all around before starting again.

Well I went out and did some more looking and found that screen Daviet mentioned. It looks to be clean. The pump runs off the top cylinder or is at least attached at that area. not knowing how the inside of the block is cast I can't really say if it runs off a particular cylinder. But I do noticed some rtv (the same color as i found in the fuel bowl) where the fuel pump is put together. So now I'm thinking someone tried to seal up a fuel pump leak with RTV and some of it migrated to the carbs.

Here is a picture from my factory manual the wording says:
recreational Models
7 this in=line fuel filter is serviced as an assembly. Replace the filter once a year


Anyone using one of these?