Difficulty starting after multiple recent repairs, but runs well after starting

We have a 1999 FourWinns 190 Horizon, 4.3GL PWTR VP engine. We had several repairs done to the engine in the past two years. The most extensive repair was when the engine was removed, rebuilt, and re-installed due to a head gasket failure two seasons ago. The engine performed ok for a few months after the repair, but then started having problems starting. Overall it seems like the starter is encountering some resistance when it engages. It will just barley start after a few attempts. Once it starts it runs just fine.

The mechanic that performed the engine overhaul has since also performed the following additional repairs, but the problem continues:
1 – Replaced both manifolds and risers
2 – Replaced the starter twice
3 – Replaced the flywheel
4 - Replaced all of the spark plugs
We performed a diagnostic on the electrical system and ruled out any electrical system issues.

Last fall we were able to get it started after a few attempts in order to winterize. We will be getting it ready for the 2017 season in a few months.

Any ideas on what we should look at next? Would an engine compression test be worthwhile?

Absolutely and/or cylinder leakdown test. Also pull plugs,inspect for water droplets,possibly partial hydro lock

Hard cranking could be a gearbox issue also. Pull the spark plugs and see how well it cranks with the starter and a fully charged battery. What drive do you have?

I'll suggest that you stop throwing parts at an issue without first paying for proper and full diagnostics.

Make sure that the shop is confident that the diagnostics are accurate.

Next...... ask for a work scope "quote" (not an estimate) stating that the work scope, as per diagnostics, will indeed correct the problem.

Next...... authorize the work ONLY upon a written work scope "quote" that references the diagnostics!

In other words, hold their feet to the fire and ask for some responsibility on their behalf!



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Now.... about your description of the issue!

When you say that starter motor has resistance and that the engine barely starts........ please explain that in more detail.
Is the starter motor not spinning the flywheel fast enough?
Why was the starter motor replaced twice? (that's 3 starter motors!)
Why was the flywheel replaced?


Yes, taking cylinder pressure readings would be good..... however, cylinder pressures typically decrease when issues come up, and that usually means that an engine will turn over more easily. It may not fire up as well.... but it will spin more easily.


Some issues are more difficult to diagnose than others. But let's not let this shop take advantage of you by simply throwing parts at it.
Throw enough parts at an issue...... and most anyone can solve the issue.

Like Click and Clack used to say........ "lift the radiator cap up, and drive a new car under it!"

Given the original repair and the money you threw at it so far...

Head gaskets rarely fail. They often are damaged as a result of other issues, usually overheat (or freeze related).
In both cases, there is usually some damage to the heads as well in terms of warping.
Sooooo, if this mechanic did not check the heads for flatness and machine if necessary, and they just replaced bad head gaskets you are looking for a repeat problem, if the original head gasket failure was caused by overheating. If the original damage to the head gaskets was the result of freezing, then the heads and block need to be checked for cracks.

In both cases, overheat and freezing, if not properly repaired, then the subsequent problem you would see could be water in the cylinders after the engine sits for awhile. This, of course will result in a mild to severe "hydrolock" situation which will manifest itself as "hard to crank".

To further complicate diagnosis, a undetected freeze problem often manifests as an overheat problem.

The test I would do if this were my boat, would be to run the engine (in the water, not hose) until it reaches operating temp. Bring it back to dock. Let it sit overnight. Remove the spark plugs and with a fully charged battery and a wide open throttle, crank the engine. See if any water comes out of the plug holes.
If none does, replace plugs, start engine, warm it up. Remove plugs and do a compression check.