228 mercruiser issues

[tkmichael11]

Im still trying to figure out my '80 228 merc problems. I have some problems that hopefully this board can help me with. The issue is stalling after running well for a few minutes then eventually failing to start all together. A few things are perplexing me. I checked the vacuum and its steady at 15 and that is with the timing at 8 BTDC which is according to the manual. If I adjust the timing to get the vacuum to 20 (which is recommended) the timing marks are way off. The air/fuel mixture is set to 2 1/2 turns on each side of the Rochester Qjet. Dwell is 28, points are set at 17, spark plug gap is .035. Should I set the timing to proper vacuum and forget the timing marks? Also, I was looking at the service manual and for my motor, it shows the number 1 wire attaching to the dist. cap directly across from the alignment notch. However, I have the number 1 attached directly beside the notch. I have put #1 on TDC and checked the position of the rotor and it points to where I have the wire. Could this be an issue? I'd love to get this running correctly before the end of summer.

 

[MikDee]

Re: 228 mercruiser issues

It sounds like a fuel delivery issue, I would check all your lines, & filters, including the one in the carb itself, and the one in the fuel tank plus the mandatory antisiphon valve there.

 

[mkast]

Re: 228 mercruiser issues

Follow the Mercruiser manual on setting the timing. A 29 year old engine might not get 20 inches of vacuum at idle with factory timing specs. A cylinder leak down test will show the condition of the engine.
When the engine stalls, do basic trouble shooting, according to the Mercruiser manual, to find out why it stalled.

 

[tkmichael11]

Re: 228 mercruiser issues

When the boat is cold it runs great. When its warm, it slowly deteriorates. I did basic troubleshooting and if I play with the timing, I can get it to run again. I've done the compression test and all 8 fall within specs. Will the leak down test show me that much more?

 

[mkast]

Re: 228 mercruiser issues

A leakdown or cylinder leakage test is similar to a compression test in that it tells you how well your engine's cylinders are sealing. But instead of measuring pressure, it measures pressure loss. While the cylinder is pressurized, listen to where the compressed air is leaking out, that's where the leak is in that cylinder.

 

[MikDee]

Re: 228 mercruiser issues

One more Item I suggest is check your fuel tank vent.

 

[Mark8625]

I have a 228 that died on the lake one Saturday with a boat load of people on board. I messed with the points for a couple of hours and couldn’t find the culprit, drove me nuts, got it home and finally found the culprit, the lubricating felt pad was completely dry and fibers from the felt pad were breaking off and getting stuck on the cam follower for the points.
Drove me bonkers at the lake because the gap was correct but with a couple of revolutions the wouldn’t make contact again. Once I figured it out I couldn’t find a replacement felt pad anywhere so I converted it to electronic ignition and never had any trouble since.