150 Crossflow Miss, Reduced Power, Speed, Tach High

[skimmabird]

I had a recent multiple failure apparently. *I lost the gears in the lower of my 89 150 Crossflow at the same time that I stripped the driveshaft splines. *I pulled back the throttle before it shot way up and turned the motor off right away to not overheat. Fortunately the crank splines looked fine still, I assume from the crank being harder than the stainless driveshaft. Well I swapped the lower out with one that had almost perfect driveshaft splines. *I pulled the thermostat housings to see if I may have melted the poppets or seals, the plugs looked good and I checked the compression and have 100-105 across, the rec./reg. seemed to be charging nicely. Everything seemed fine so I dumped the boat back in the water. The motor performed normally as I putted down the canal. *When I bumped the throttle to 3000 the motor stumbles and misses some. *Then the miss lessons after being planed out but it definitely has a miss and reduced power and speed for the rpm the tach says. The rpm seems correct under the light load of 800-1500 but after that the sound just doesnt match the tach. The tach doesn't come close to what the speed should. I'm getting 18mph for 3500 rpm and should be about 25mph at 3500 normally. The tach sweeps to 6100 at 39-40mph. It should be like 5500 and 45 mph normally. I checked all grounds, wires, connections, advancer. I was thinking maybe the rec/reg was shot but it's a year old BRP part and seems to charge normally. Now I'm thinking power packs, coils, timer base, stator. What are my next steps guys?

 

[emdsapmgr]

Re: 150 Crossflow Miss, Reduced Power, Speed, Tach High

Sounds like a major lower unit failure. Possible that the failure was due to impact damage. If so, possible that the prop was also damaged, perhaps the hub. Any chance that your current test is with that propeller? That could account for erratic rpm's and lack of speed.

 

[skimmabird]

Re: 150 Crossflow Miss, Reduced Power, Speed, Tach High

Sounds like a major lower unit failure. Possible that the failure was due to impact damage. If so, possible that the prop was also damaged, perhaps the hub. Any chance that your current test is with that propeller? That could account for erratic rpm's and lack of speed.

Stainless prop's perfect, hub is not spun. Sorry I probably should have mentioned it.

 

[emdsapmgr]

Re: 150 Crossflow Miss, Reduced Power, Speed, Tach High

You seem concerned that you may have overheated the powerhead. If the powerhead was run for a brief period with insufficient cooling water in the block-it is possible that the rectifier/regulator got fried. It is water-cooled and fries easily if water is not circulating properly to the top/underside of the block. A bad rectifier/regulator can cause erratic tach operation. Possible the engine may not be recharging the battery.