Engine Cuts Out at High Speeds - Sometimes (1990 PCM 351)

[djm284]

Hello All,

Took the boat out for the first time on Monday after making the folllowing repairs/maintenance for the season:

- New Fuel Pump and Line
- New Starter Motor
- Installed Sea Strainer and Ball Valve
- Converted from 20w to DexMerc Trans Fluid (changed 3x)
- Replaced Worn Hoses
- Oil/plugs/coolant/impeller/battery charge
- Mostly new fuel (rest had adequate stabilizer)

I'm running the original PCM 351 (1990 Sunsport). It ran well all last season and ran beautifully on Monday with the new fuel pump, until...

We were out about 2 hours running at various speeds (anchored, idle, slow, almost full throttle). Saw a storm approaching, so took cover under a bridge while it passed. By "took cover" I mean we putted around between idle, low speed forward, and low speed reverse for about an hour. Once the storm passed, we decided to head home because more rain was predicted. But now, everytime I tried to go faster than a very low speed, the engine cut out. We were able to get home (about 15 minutes) at very low speed. Kept trying intermittently to increase speed a bit but every time the engine would cut out. Today I ran the engine in my driveway (with garden hose connected). Running nicely now. Let engine warm up, and still running nicely.

Any thoughts on what this could be and how I could test it so we dont end up getting stuck out on the water? Again to summarize: Engine was running great, putted around for an hour between idle and low speed, then engine would cut out every time we tried to go above a low speed, runs fine in the driveway today.

Much thanks!

Dave

[djm284]

a couple other notes:

- replaced oil pressure sender before taking out (dont think that should affect this)
- retrofitted with standard distributor a couple years ago (i.e., no more protec)

[djm284]

...also replaced oil and fuel filters before running

[OUI]

Sometimes a plugged breather tube to the gas tank can cause that problem. If it happens again, unscrew the filler cap to the tank and see if that clears things up.

[djm284]

will try that, thank you!