Mercruiser 228 inboard running issue

[akwalker]

Having a bit of a problem with the engine above. Engine starts and idles fine. Will run at throttle fine for about an hour. After a run, and then an extended trip at no wake speed, the engine will not reach operating RPM, misses, smells of exhaust and has no power over 3000 RPM. I have rebuilt the carb, changed the fuel/water separator and added an additional inline fuel filter. I get the same result. Previous owner had changed from points/condenser to Pertronix electronic ignition. I'm thinking that there is a problem with it. The engine acts just like the timing is not advancing. If we sit at the dock or at anchor for an hour or so, it'll run normal again for about an hour, and then act up as described. I really don't think its a fuel delivery problem. Any ideas?

BTW, coil is new, plugs and wires are new.

Thanks!

 

[rich1295]

Re: Mercruiser 228 inboard running issue

I had a similar problem with my Mercruiser 228. Ran fine for a while, but choked up after a while at full throttle - eventually not running at all. I also tried many things - tune up - replaced filters etc. Problem turned out to be gunk in the fuel tank. You said you have an inline fuel filter. Does it have anything trapped in it? I had a fancy one, but found a regular NAPA 23003 filter worked best - I can see when there is stuff in the line. I ended up having to remove and clean the 70 gallon fuel tank twice to eliminate the problem. Still keep the inline filter in place though and end up replacing it every few months.

 

[akwalker]

Re: Mercruiser 228 inboard running issue

I had a similar problem with my Mercruiser 228. Ran fine for a while, but choked up after a while at full throttle - eventually not running at all. I also tried many things - tune up - replaced filters etc. Problem turned out to be gunk in the fuel tank. You said you have an inline fuel filter. Does it have anything trapped in it? I had a fancy one, but found a regular NAPA 23003 filter worked best - I can see when there is stuff in the line. I ended up having to remove and clean the 70 gallon fuel tank twice to eliminate the problem. Still keep the inline filter in place though and end up replacing it every few months.

I installed the inline filter on friday. Went for a few hour ride Saturday, and looked at the filter this morning. It looks clean. The thing that puzzles me is the exhaust smell. Its not the smell of raw fuel, but rather heavy burnt exhaust smell.

 

[rich1295]

Re: Mercruiser 228 inboard running issue

I installed the inline filter on friday. Went for a few hour ride Saturday, and looked at the filter this morning. It looks clean. The thing that puzzles me is the exhaust smell. Its not the smell of raw fuel, but rather heavy burnt exhaust smell.

Sorry, that's all I can give you, I'm not a mechanic, but it sounded similar to my problem. My boat mechanic actually road with me and couldn't find the problem, until I installed the new inline filter. Sounds like you have some other issue. Good luck.

 

[NHGuy]

Re: Mercruiser 228 inboard running issue

I am not a Pertronix expert, but I can say there are a number of ways they are set up. If your fuel supply is good and you're not getting hot inside the engine compartment (vapor lock) you might research the correct way to wire & run the Pertronix on your boat. You need to have the right coil, and resistance wire (if used). It's confirmed with voltage tests. When things are wrong you get overheated electrics which quit functioning. Lots of folks on here understand them. I'd think it could be be that.
It could also be crud in the fuel tank catching on the pickup, but since you have clean filters I'm more inclined to think ignition.

 

[Stamey]

Re: Mercruiser 228 inboard running issue

What is the temperature of the engine when you are having problems?

Chris

 

[akwalker]

Re: Mercruiser 228 inboard running issue

What is the temperature of the engine when you are having problems?

Chris

Engine temp is normal, right around 140-150 degrees with a 142 degree stat.

 

[akwalker]

Re: Mercruiser 228 inboard running issue

Found the problem First, I wanted to thank all those that responded, I really appreciate it.

After much troubleshooting, and ruling out, I found that the Pertronix electronic ignition that the previous owner had installed was at fault. I checked the timing at idle, and faound that it was about 16 degrees BTC instead of 8. Changed the timing to 8, and took the boat for a run. It was worse than ever, just would not make power, so I started advancing the timing a little at a time until the boat ran reasonably well. After about 15 minutes, it started running like garbage again. I checked the timing, and it was back to 16 degrees BTDC at idle.

Found a local marina with a used Mallory, points equipted distributer. Sold it to me for $50.00. Installed the breaker plate, points and condensor. Gapped the points, set the dwell, and went for a ride. Boat runs like it should.

There's alot to be said for old school ignition systems!!

Thanks again.
_________________
1981 F-26 hardtop
"Gracious Lady"