1956 mk30h 30h

[fishdady]

Friend brought me this engine to get running. Sat since 1982. It's got the quicksilver LU. Got it going, then put new points, condenser, wires, impeller, rebuilt carbs and fuel pump. Compression was 120 on all cylinders. Now it runs for a while , then quits.Today after going over everything I have done, fired up, ran awhile then quit. I put a primer bulb on the line, pump the bulb while it runs, keeps running. I have worked on johnnie/rides, but no master mech. There's a block off plate where a 2nd fuel pump apparently once was. Does it need a second pump. This engine goes on a hydroplane he raced as a kid and still has the boat. Wants to get it running again. Thanks for any help or suggestions to try. Chuck

 

[DeepCMark58A]

I believe there was only 1 fuel pump on the motor, mercury did not go to 2 fuel pumps until the 6 cylinder motors.

 

[DeepCMark58A]

What is the condition of the fuel tank? How do the fuel lines look?

 

[fishdady]

What is the condition of the fuel tank? How do the fuel lines look?

Used a rude tank, fresh gas and lines. Have access to the small, maybe 1 gal. Tank he used in the day. He told me that they never used a bulb or connections because they were told they were too restrictive. Something about blowing air in the tank to get fuel to the carbs. Don't know how that works,thought I would throw that out there. Thanks for the respnses!

 

[Chinewalker]

How are the check valves in the fuel pump? If they're worn, you won't get full flow. Make sure ful tank is vented. You might be able to see if fuel pump is flowing by routing a hose from the OUT into a coffee can and roping it over. Also, did you set the float needle lever height as per the book?

The stock Mark 30 ran two pumps, but the 30H used only one. I run a bulb on my 30H with a 1-gallon steering bar mounted tank without issue, running 5/16 hose.

 

[DeepCMark58A]

Did not intend to give bad information about the fuel pump, the mercury manual I referenced for years 1955-1965 stated that 4 cylinder engines in this era only had 1 fuel pump.

 

[fishdady]

Check valves are new and position right. Checked float drop, but, will recheck. Both idle screws were set at 1 1/2 turns initial. Now out to about 2 1/4. Didn't think bulb or connections would restrict. Thanks to all!

 

[fishdady]

Sorry, chine to answer your question, did check flow of pump, was good. Tank was vented, then tried closing vent. Since it had a pump on it I was sure it needed vented. Closed vent as a trial. Thanks

 

[Chinewalker]

Stupid question, but is the pump base/spacer block under the fuel pump? I ask because I had a Mark 55 brought to me many years ago with that block missing. Diaphragm was flat against the boss on the block and wouldn't flap. Found him a pump base block and it worked fine. Someone had left it out at some point...

 

[fishdady]

No stupid questions. Especially when your trying to help me. Yes the blocks there. Thanks

 

[Chinewalker]

Do you have a second pump? It certainly won't hurt. You're not racing, so you're not breaking any rules. That priming bulb keeps it going seems to help certainly point to fuel flow. Maybe try it with the bulb removed?

 

[fishdady]

Read my mind, was going to try without the bulb as a0 shot. Don't understand how it gets and maintains a prime, tho. Off tomorrow and take carbs apart, see if I missed something in there. Thanks!

 

[fishdady]

Went through everything I did, give it a try tomorrow, let you know (chinewalker) Wish I did have another pump. Will check fuel pump first. Thanks for your help! Chuck

 

[fishdady]

Got the old girl going. Have to admit, check valves in fuel pump were backwards. Thanks for your help!