New Member New Boat

[Isaiah215]

My new to me 1990 Wellcraft 215XL W/ 5.7 Merc. My first vessel. I’ve been out a few times this month now. It’s not perfect and I’ve got some stuff to do on it. The water manifolds seep to the outside. After taking it out I have discovered a low power issue. I replaced plugs,wires, distributor cap and rotor just for keeps-sake and it being old without any records of replacement. I’ve got a decent studder on “ahead full” position with a general consensus of not being able to top 3,400 RPM with myself, full tank of fuel in it. I’m assuming I have an issue with accelerator pump and secondaries. I plan on verifying fuel pressure and then looking into the carb. Points system.

[DaveKamp]

Very FIRST PROBLEM... Water seeps out of ANYTHING.

Set aside the 'low power' issue, and get on the 'water seeps from' issue, as you'll find out really soon that you have NO power... and nobody to tow you back to the dock. The power problems and stutter you're seeing, are probably somehow related to the fact that you've got some OTHER problem somewhere.

Throwing random parts at it will wind up with you having even more problems, PARTICULARLY if you start throwing automotive parts into a marine environment.

Marine cooling systems are very special. You have water being brought in from the outdrive, lifted into the engine with an impeller pump IN the drive, through a hose in the gimbal, past a power-steering cooler to the circulatory pump (on front of engine). From there, the block gets filled, and the circulatory pump flows water through the block and heads. While this is happening, all that raw water coming in is dumped out through the manifolds, over the riser elbows, into the exhaust path back out through the drive or transom. Once the engine is warm, the thermostat allows high temperature water (block and heads) to pass out into the manifolds and risers, while allowing a little raw water in to replace what's leaving the engine loop.

Your '90 PROBABLY has a crossover passage between left and right cylinder heads for a choke stove. It is probably plugged up.

Your exhaust manifolds are probably original to the boat. Marine environment is hard on cast iron marine exhaust manifolds, not only are they exposed to heat cycling, they also wind up with sediment blocking the drain passages, and if they're not properly cleared and drained in winter, they freeze and crack... but even if they ARE winterized properly, they thin out over the years, become brittle, and then leak.

There's a dozen-or-more other things that you should attend to in 'old boat' world. The engine coupler is a rubber cup with a splined center. The rubber eventually dries out and fails, causing the splined center to slip, melting the rubber, and flinging hot-stinky-sticky goo all over the inside of the transom, and leaving you stranded, with a running engine, but a non-spinning drive, and shortly therafter, an overheating engine (because the drive isn't spinning, thus not providing cooling water to the powerhead).

A high-speed stutter can be sign of a slipping prop hub, ventilation/cavitation, a shift interrupt switch tripping from transom flex... a plugged up fuel filter, collapsed fuel line or plugged up anti-siphon valve...

[DaveKamp]

The most simple scenario for unable to get past 3400rpm is simply that your drive trim isn't up high enough for the hull to lift any further.

When propped correctly, you should be at 4800rpm at full throttle and highest state of plane. Do NOT let it run at over 5000 for ANY length of time, as the MerCruiser R/1R/MR/Alpha/Alpha One/Alpha One SS series will NOT tolerate it for any length of time. The gear oil is cooled by two things- first is water contact through the lower unit casting, second is by raw water passing through a short area in the upper housing between the top of the drive unit water pump, through to the fitting to jumper hose going to the inner transom housing fitting. Drive lube circulates around the inside of the upper and lower drive sections by virtue of the spinning vertical shaft... and as it does, heat is transferred from gears to the housings... but once the upper shaft exceeds that 5000rpm range, oil is flung off too quickly to absorb gear heat... and the gears melt.

Don't ask how I know...