Starboard engine runs bad below 1200 rpm in gear

" I have an old Chris Craft, 1

" I have an old Chris Craft, 1976 35' Catalina. The
starboard engine run fine above 1200 RPM, but when
I come in to dock, the engine keeps dying. When it does run it sounds like it is missing or the trans is banging. I have changed fuel filters and dumped 96 oz of isopropyl alcohol into each of my 75 gal fuel tanks, no help. I just got the boat at the end of July, and the family and I crusied up to the San Juans for 8 days in August. The engine died a couple of times, no big deal. Now it happens everytime. If the prop shaft is hard to turn, by hand, could that cause my problem? There are a few more things to try on the engine, tune up, carb rebuild, but I was wondering if anyone has experienced this problem before? Thanks in advance for any response.
Lloyd "

"Lloyd, it does sound fuel r

"Lloyd, it does sound fuel related, but I'd first make sure by checking for spark when the engine dies. If the plugs spark and the coil is not overheated, I'd then work my way through the fuel system with special attention to the fuel pump and fuel pressure. A failing fuel pump would cause the situation you describe. Also check and clean the fuel line filter in the carb - I'm thinking you have a Rochester Q-jet.

On a boat that old, fuel contamination is always a possibility, but that would probably not be confined to below 1200 RPM. Keep checking your filters, though.

If you have Paragon hydraulic gears, the prop will have a lot of resistance to hand turning - that's normal.

"

" Lloyd,
Even if you susp

" Lloyd,
Even if you suspect fuel problems it is cheap and easy to go through the ignition system and rule that out. Replace the components one at a time and see the results. Observing the condition of the spark plugs may give you a clue. Check the points. They could have slipped or gotten damaged.
Eddie "

" Croozer,
I don't think

" Croozer,
I don't think it is a ignition problem, because I can go for hours at 3000 RPM, just when I go to pull into my slip. It also happened right after I start up, try to back up, and the engine would die. It runs fine in neutral, revs up, idles, no problem. I put it in gear, and have to play with the throttle to get going. Above 1200 RPM, runs fine. The engines are 350Q's. Haven't had the spark arresttors off to see what kind of carbs I have. Really I'm just getting started troubleshooting this problem. But the fuel pump does sound suspect. Had a similar problem at my work, had a aircraft ground power unit that would run up to speed, but would not idle. Changed the fuel pump and that fixed it. Sometimes it takes another set of eyes to see the obvious problem.
Thanks for the tips,
Lloyd "

" Eddie,
I have pulled one sp

" Eddie,
I have pulled one spark plug and it looked fine. Points, I've got to get rid of 'em. Haven't had points since my '65 Barracuda. But seriously, thanks for the advice. I do need to upgrade to an electronic ignition, some day.
Lloyd "

" Lloyd
Could still be ig

" Lloyd
Could still be ignition. I'd replace the distributor cap and rotor. After that I'd check or replace the spark plug wires. The symtoms, if it's an ignition problem, seem to lie in that area.
Eddie "

"One more thought, if you are

"One more thought, if you are running a Q-jet and the fuel system checks out okay and your carb's fuel circuits are clean, try adjusting the low speed mixture control screws (2 screws underneath the air horn in the "front" of the carb). The mixture may be too lean. Adjust them evenly until the engine idles smoothly in gear.

"

" crooser & Eddie,
Went d

" crooser & Eddie,
Went down to the boat to check things out. I have a Carter carb on my engine. I popped the distributor cap off and found a crack between # 3 and #4 contacts. Bought a new cap and installed. Seems to have fixed problem. I put the starboard engine in reverse tied to the dock and at 500 RPM, the engine ran smooth and did not die. I'll have to get the "crew" aboard and take the boat out for a real trial, but I think I found the problem.
Thanks guys for the help. I used a similar forum for Dodge trucks to reaserch a problem and I'm glad I found one for the old Chris Craft also.
Thanks again,
Lloyd "